Strongly Recommended:
-Little Big Planet 1/2 (If you're gonna buy LBP 1, buy the GOTY edition, and if you can, turn it over when you finish it, as it's mostly only for objects/costumes for 2)
-Uncharted 1/2/3 (3 will be out on November)
-God of War 3/Collection (Collection if you don't have the originals, unless you're a trophy whore)
-inFAMOUS 1/2 (2 will be out on June 7)
-Heavy Rain
Haven't played, but seem cool:
-Ratchet & Clank
-Gran Turismo 5
-Twisted Metal (It will be out sometime this year, I think)
-Final Fantasy Versus XIII (It will be out by the end of this year, I think, if it's not delayed)
-ModNation Racers
-Metal Gear Solid 4
If you like Shooters:
-Resistance 1/2/3 (3 will be out on September, 1 & 2 are going to be in a collection pack on June)
-Killzone 2/3
And since you are planning to buy the Team ICO collection, you should try The Last Guardian (It will be out next year I think).
-Little Big Planet 1/2 (If you're gonna buy LBP 1, buy the GOTY edition, and if you can, turn it over when you finish it, as it's mostly only for objects/costumes for 2)
-Uncharted 1/2/3 (3 will be out on November)
-God of War 3/Collection (Collection if you don't have the originals, unless you're a trophy whore)
-inFAMOUS 1/2 (2 will be out on June 7)
-Heavy Rain
Haven't played, but seem cool:
-Ratchet & Clank
-Gran Turismo 5
-Twisted Metal (It will be out sometime this year, I think)
-Final Fantasy Versus XIII (It will be out by the end of this year, I think, if it's not delayed)
-ModNation Racers
-Metal Gear Solid 4
If you like Shooters:
-Resistance 1/2/3 (3 will be out on September, 1 & 2 are going to be in a collection pack on June)
-Killzone 2/3
And since you are planning to buy the Team ICO collection, you should try The Last Guardian (It will be out next year I think).