I'm no computer expert, but the rule of thumb is you get what you pay for, and laptops always cost a hell of a lot more than a similarly performing desktop. I have no idea what games you have in mind, but if they're pretty new, you may be expecting to dish out a few hundred dollars, at least.
Generally, if a laptop is advertising a fairly nice graphic card (like an Nvida or ATI), has a good processor (Like an Intel i5 and up), and good RAM (let's say about 6-8 gigs for something half decent), then it's probably close to what you're looking for for newer games. Won't be perfect, but it should be able to run most of the games that came out in the past couple years.
However, if you want to play the newest and greatest games ever, you might as well spend the money on a good desktop. Gaming and laptops generally don't go hand in hand.