As everyone else has said, Dead Rising is a blast. One thing about the save system that everyone complains about. Just play a while have some fun, then when you die choose "Save Status and Quit" You start the game back from the begining but you keep all your stats and levels, so much fun when you're stronger, faster, and can hold more items.
I liked Need for Speed: Most Wanted, which is kinda funny because I usually don't like racing games.
DOA4 got kinda boring for me, had some fun playing with other people, but not very fun solo play at all (for me).
Condemed was pretty fun and creepy.
Perfect Dark 0, wasn't very fun, but then again I was expecting something like the orignal one and it's not at all.
The one that I continue to play over and over and over again has to be Dead Rising. I love that game. Here's another little tip/fun thing. When you start the game at the part when you have to go outside to reach the other side of the mall, go near the pond and get the sickle near a bench, that's fun. Then go towards the door you're supposed to go through but head to the right into the parking garage, grab the car and head back out to the grass and have some fun driving over zombies, then go to the door you're supposed to go through and grab the lawnmower (kind of a tricky item to use, if you push the button at the wrong time you pick it up) and start mowing away.....ahhhh sweet zombie killing bliss. I personally can't get enough of this game.