Get on Live and download Braid, Monkey Island SE and Shadow Complex.
RPG, get Vesperia. Star Ocean 4 is a massive time-sink (but the story still sucks). If you're into action however, the newly released Arkham Asylum is mad fun. Play that Dead Space; that's another good title. Some here told Saints' Row 2; that's also fun. Prototype is a tad bit short; rent it first. Same with Wolverine: Origins. If you're into racing or cars in general, you can't go wrong with Burnout: Paradise or GRID. Fighting was mentioned: BlazBlue. Or Street Fighter 4 if that's your thing. Shooters (if you play it here) include Modern Warfare, Wolfenstein (rent only), Orange Box (best bang for your buck, honestly) and so much more. Music games? Rock Band and its sequel. Do get it.
If you're still stumped, check out
Metacritic and look for games there. Look at the top hits or specific genres of you're choosing and look at the high marks. It should tell you what to get and such.
Jam it back in, in the dark.