Following Miss Capn's trend just so I know where I'm at! :) 
[hider=Matt's Relationships]
[color=aqua] Rafe Guttierez [/color]
Relationship towards them: Highly respected friend. 
How does your character personally feel about this person?: I think secretly Matt looks up to Rafe. He just seems to have everything together. Regardless of how much he actually does, he always seems like it. 

[color=aqua] Avery Rydell [/color]
Relationship: A little stand-offish. 
Feelings: Doesn't fully trust Avery. He's ran into girls that look like her before. There's something intriguing though. Something he can't quite figure out. It's that thing that allows him to try to build a friendship.

[color=aqua] Maximus Santos [/color]
Relationship: Friends 
Feelings: Max seems to be a very understanding fella. He helped Matt out, and it's a debt that Matt intends to pay back. In the meantime, Matt's going to do all he can to crack Max's fairly serious demeanor.

[color=aqua] Alexei Malakav [/color]
Relationship: Friends 
Feelings: Matt is excited to learn more about Alexei. He has a bit of a disillusion of grandeur about him. In Matt's mind Alexei is a trained assassin, or a brutal bare knuckles fighter, or just an all around rough guy.

[color=aqua] Johanna Sanchez [/color]
Relationship: My sister from another mister...
Feelings: They fight, they get on each others nerves, but at the end of the day there's a connection that's real. Matt working for Warren in the past may occasionally bring out some hard emotions, but Matt enjoys knowing that Johanna trusts him.

[color=aqua] Anastasia Carver [/color]
Relationship: Good Friends 
Feelings: She's beautiful. When Matt pursued his bet of going out with a model, Stas wasn't anything like he thought she'd be. Although the attempt was unsuccessful, Matt kind of sees himself as a protector. He does what he can to keep Stas away from the wrong kinds of people.

[color=aqua] Luci Becker (Haven't discussed anything so this can definitely change!) [/color]
Relationship: Great Friends
Feelings: Luci is the kind of person Matt can hang out with and shut his mind off. There are a lot of natural similarities between the two, and that has always put Matt at ease around her. He wishes maybe she'd slow down a bit, but there's better than sitting with her with a beer in hand, and nothing going on. 

[color=aqua] Marcie Belmonte (also haven't discussed, just a guess) [/color]
Relationship: Friends 
Feelings: Matt can't help but find Marcie funny, even when she's not trying to be. He finds himself apologizing to her a lot! He doesn't purposely try to annoy her, but some of her mannerisms are just so uniquely amazing in his eyes, he can't help but laugh. 

[color=aqua] Spencer Rivera [/color]
Relationship: Best Friends 
Feelings: Spencer's hours may not leave them much time to actually hang out, but when they do it's as if they both take on different personalities. There's a comfort, and a freedom that lets them be themselves. Which in general is pretty carefree and happy. When hanging with Spence, everyone around them is going to have a good time whether they like it or not! (Note for me: Shared interests play a part too)

[/hider]

So yea I was thinking either Rafe or Spencer for a roommate, but I'm open to whatever! All of this is open to change too! Some of those feelings about people will obviously change as the story advances.