I'll go countdown style, because reasons. Also I won't include multiple entries from one series because that's lame. I'll just throw my favorite from a given series in the slot where it belongs, and any others I feel like talking about will go in the honorable mentions area.
10. Bastion - The game play is pretty solid, but Bastion's atmosphere is what really drew me in. The narrator and the soundtrack took it from being just a good action RPG to an amazing experience. The story is also pretty good, and though there are only a few named characters at all it managed to pull me in enough to feel attached to them all, and that's something I can't say about the majority of even the games on this very list.
9. Warcraft 3 - This was a mainstay of my childhood, and it's still a great game today. The single player campaigns (particularly with the Frozen Throne expansion, loved the whole founding of the Horde campaign thing) were great both in game play and in the story, and that's where I spent most of my time playing this game. I delved into some of the online stuff, but I was a shitter and sucked at competitive play (the slow build turtling I learned against the campaign AI on normal difficulty did not work against anyone who knew what they were doing). Still had tons of fun in the online play anyway, and I wish I still had my original account to be able to check how many hours I played. Pretty sure it had to be over 200, including my multiple plays through the singleplayer campaign.
8. Super Metroid - This was actually the first video game I ever played, though that's not why it's on my list. The combat is simple but solid, the platforming is pretty damned precise, and the exploration aspect is fun rather than infuriating (at least for me, as I know plenty of people who hate this game for how hidden some required equipment upgrades are). I never sunk as many hours into this as with some of the others on my list, but that's only because I got to the point where I could blitz through it in a few hours whenever I felt like replaying it again, and the number of times I've played it through while still enjoying it is probably the main reason it's in my top 10.
7. Illusion of Gaia (called Illusion of Time in Europe and Australia) - A SNES game that most people seem not to have heard of. It's a fun action RPG game with a solid story and cast of characters. Nostalgia is a large reason why I count this game in my top 10, but the game itself still holds up today. It also has the distinction of being the first and almost only video game to ever make me cry, because young Jorick couldn't quite handle some of the shit that went down in the story.
6. Dragon Age: Origins - This was a hard one to place. Played the shit out of it, loved it, but hard to compare to some of the other games on the list. It combined two of my favorite things in games: RPG elements and tactical fighting. It also helped that the story was pretty good shit and the characters were generally well fleshed out. The world itself was kind of the star though, with all the great lore popping up all over the place. It was one of the few games that made the extra reading in books and journal entries and such feel like a worthwhile experience instead of a tedious thing to ignore, and that alone earns some points in my book.
5. Dark Souls 1 & 2 - Already breaking my rule about one entry per series, but fuck it. Both games are pretty equal to me, in that they're both great. I love games that don't hold my hand the whole damned way through and present real challenges for me to overcome, and those two things are Dark Souls in a nutshell. I've spent over 100 hours in each of them separately, and they're still fun to me. That says a lot, considering how I get bored of most games after a couple hours and never bother with them again.
4. Yoshi's Island - It was hard to pick between this one and Super Mario World, but in the end I had to decide that the higher quality game had to win out over the one I had more nostalgia for. Yoshi's Island is the best platformer game I've ever played, bar none, and I rather enjoy platformers so I've played quite a few of them. It'd deserve a top 10 spot just based on how great the game feels to play on a basic level, with jumping that has just the perfect amount of slipping and sliding around to make you feel like you're in control of something with actual weight and momentum behind it, but the other mechanics of shooting eggs and having your life based on keeping baby Mario safe are great additions to the typical "jump over this gap and the next one and so on until the end of the level" formula of platformers. The art style is pretty great too, probably one of the best looking SNES games ever, so bonus points for that.
3. Fallout 1 & 2 - Since I already broke the single entry rule, fuck it, this is another one where it was hard to pick one over the other. Remember that thing I said in the Dragon Age: Origins explanation about loving RPG stuff and tactical fighting? Fallout 1 & 2 had a large hand in getting me to love those things to begin with. Remember that thing I said in the Dark Souls explanation about loving it when games don't hold your hand and instead give you a real challenge? Fallout 1 & 2 were some of the first games that made me work through frustration and difficulty to get to that sweet feeling of victory on the other side. The modern revivals of the series can get right the fuck out of my face with their mindless fighting and how they baby you along to the right path, these two games are what Fallout is all about.
2. The Elder Scrolls III: Morrowind - I've mentioned playing some games on this list for over 200 hours; Morrowind makes those look like jokes. I've played it frequently over the lifespans of two original Xbox systems, two Xbox 360s, and on my computer, and in total I've easily surpassed 1000 hours played in this game, probably closer to 1500. It's kind of disgusting, but it's also so damned good. This was the game that first introduced me to the rich lore of the Elder Scrolls world, and it was my first experience with a truly open world game where you can do damn near anything. It's another one of those games that throws you into the world without much to go on and then tells you to get out there and do shit. It's not so heavy on the challenge side of things, but it more than makes up for that with the freedom and lack of treating the player like a child. The graphics don't really hold up at all, and the combat wasn't all that great, but it was a fantastic experience every step of the way. It really gave that feeling of being an adventurer on an epic quest, along with that ever-present feeling of freedom to do as you please, and that combination is something I've yet to find in another game. If not for those couple flaws I listed, Morrowind would probably be my #1 game.
1. The Legend of Zelda: A Link to the Past - This shit right here was my fucking childhood. It was one of the first games I ever played, and I played it for hours and hours and hours a kid. Couldn't even get past the first part of the game and into the Dark World until I was about 10, and didn't actually beat the thing until I was 15, and that felt like the high point of my life for years man. This is one of the very few games I can actually play over again and still enjoy, and I love it every time. It's a fucking masterpiece of game design, and even at its worst points (such as the water and ice dungeons) it's still great. The combat is a perfect example of a simple concept done so well that you don't even need complexity to make it compelling. Everything from the music to the sound effects to the art direction are just fucking wonderful. I cannot think of a single negative thing to say about the game, and that's probably why it's got the top spot of my list locked down. I could go on for many paragraphs about why A Link to the Past is so damned awesome, but I think I'll just cut myself off here instead. I dunno if any other game will ever take this top spot away, because the combination of amazing game and hefty nostalgia is goddamned formidable.
Other Legend of Zelda games - This series is one of the reasons I decided to only have one game per series. Ocarina of Time and Majora's Mask would have both made the list without that stipulation (OoT probably at #3, MM somewhere more like #8 based on what games I have in those slots currently), at the very least, and I figure Windwaker would as well if I ever played it (never had a Gamecube, never felt inclined to get one just for the one game). I've never played a Legend of Zelda game that I didn't enjoy a lot, and I've played most of them.
Other Mario games - Super Mario Wold and Mario 64 would have also made the list without the one per series rule (probably #5 and #10 respectively). Both are pretty damned good games, but Yoshi's Island was better so it won the Mario slot.
Portal 1 & 2 - If it were a top 15 list with the same one per series rule, Portal would've made it. Alas.
Civilization 3/4/5 - Another that might've made a slightly longer list. Probably would've been Civ 4 to rise above the others, for those who care.
Knights of the Old Republic - Same story as the above two. Didn't care so much for the sequel though.
Fable - Another that would have made a top 15 list. Not the greatest of games technically speaking, but was quite fun in its time.
Final Fantasy - One of the games from this series, probably 3 (of the American releases, the one with Terra), probably would have made the #15 slot in a longer list.
Fallout 3 and Fallout New Vegas - Despite the shit talking in relation to Fallout 1 & 2, they're still decent games. Not worthy of my top games list, but still good.
Skyrim - Better combat and graphics than Morrowind, but that's about it. Still a damned fun game that I spent a couple hundred hours in total playing, but it just didn't have that same feel that made me love Morrowind and is not good enough in my opinion to make my top 10 even if I didn't have the one per series rule going. Oblivion probably wouldn't even rank in a top 50 list for me though, so Skyrim has that one beat at least.
World of Warcraft - Just because of time sunk into the game alone, WoW almost made it on the list because of effort justification. But then I remembered that the game itself wasn't that good and most of my time played on it was roleplaying or using it as a glorified chat program while running around the cities, so it got bumped down here instead.
Diablo 2 - Speaking of time spent in Blizzard games, here's another one that consumed a large portion of my life. Similar story with WoW, almost felt like including it on the list because of the time factor but the other games listed were just straight up better games.
Minecraft - Another game I've spent hours and hours playing, mainly because any game can become enthralling in multiplayer and that's where I've spent most of my Minecraft hours.. Not really good enough to beat any of the top 10 games on merit alone, so here it remains.