I second checking out both Uncharted and Uncharted 2, Ratchet and Clank games, and God of War Collection. I also suggest Burnout Paradise if you like racing games.
If you are a fan of the series, Tekken 6 is cool, but make sure you get it sub $30 if possible.
If you can find it on sale, DJ Hero is super fun.
Even though it has its issues and isn't the great game that it had the potential to be, I am enjoying Dark Void...but make sure you get it cheap or you might feel a tad bit cheated.
Of the games coming up, God of War 3 might be a must buy along with Final Fantasy XIII if you like RPG's. Heavy Rain is high on my "to buy" list (right behind the previous two), but I will wait for a few reviews to come in before pulling the trigger...this game with either be a masterpiece or a colossal fail...
[quote name='Gaming Dude']Get Valkyrie Chronicles, Uncharted 2, and Demon's Souls.[/QUOTE]
I would definitely check out the demo of Valkyria Chronicles before buying...I heard so many great things about it, and while interesting, it wasn't really for me.