Crysis can be had for cheap if you shopped around. And yes, it can run on that laptop with EDIT: ALL of it's prettiness turned on (don't believe me? Download the non-optimized demo and prepare to be blown away, keeping in mind that the retail release is 100x prettier). I think the EA digital store still have that promotion going ($20 off a game or something), so you could get Mass Effect 2 fairly cheaply. Direct2Drive did a perma-price drop on The Witcher, which is another game if you're really into PC RPGs (and there's nothing wrong with that). Like scary FPSRPGs? Try the STALKER series, which would run nicely on that new laptop.
How about COD Modern Warfare (the first game), since last time I check they still had a fairly big online player population. If you want Doom 3 old, then you're really selling your hardware short. But if you insist, Unreal Tournament 2k4 is an excellent game from the era, and can be bought for under $20. Come to think of it, UT3 Black is $20 on Steam, but I never noticed alot of online players for that game.
How about a racing game? Burnout Paradise is an older title, but would really look pretty on that 15.6in screen of yours. Trackmania Nations Forever is a free game, and though I could run that game on an intel x3100, do yourself a favor and pick it up nonetheless.
Red Faction: Guerrilla, a good sandbox game for the PC, but you might have played this on the console already.
RTS? Company of Heroes, Supreme Commander 1, Command and Conquer 3 (or Red Alert 3), or even Dawn of War 2?
Dungeons and Dragon Online is Graphically taxing, but free to play MMO, and that's really cheap (as in, free). You could try "Demo-ing"
Global Agenda, the MMO FPS RPG. No monthly cost for the basic, mmo-lite version, but I think the game itself retails at around $50 still.
