I fully enjoyed Metal Gear solid 4, but if you weren't THAT into the hype, you probably won't dig it as much :P So I'm NOT going to spam the reccomendation for it.
Uncharted was absolutely amazing.
Same with Ratchet and Clank futures ^^
Warhawk is a damn impressive title that refuses to let you stop playing once you get the ropes down >_E It's too godamn hard to put it down!
But like I mentioned, get a PSN first, and pick up Super Stardust!!!! It's like 10 bucks, and full of awesome :D No excuse not to! Same with Pixel Junk Eden and or Monsters ^^
From 0 to KICKASS in .stupid seconds.