[arsenal]

Depends on what you are looking for:

Halo 1 & 2 -- Passed Halo 1 in a week. Halo 2 is more story laden. The gameplay is pretty much the same as the first one. Rent it for about a week, and you will probably pass it.

Full Spectrum Warrior -- I really liked this game. You get to play as the squad commander of 2 US (marine?) fireteams. There a story to it, although I forget what it is, but it is squad based action. The reason why I like it, is because you actually have to think about what you are doing. If you rush around a corner, most likely, your entire fireteam will be dead. It was developed for the US Army, and is used by them for training.

Need For Speed Underground 1 & 2 -- These are kind of "specialty" racing games. But I find that they are fun. You get a car, and enter races, contests etc, go get money. With your money, you can then get new vehicles, or modify your exsisting vehicle. Its a street racing game.

Project Gothom Racing 1 & 2 -- This is sort of Xbox's answer to Gran Tourismo. You get to drive around in a bunch of super cars. Not sure if you get to upgrade them like in Gran Tourismo, as I didn't get that far into it.

RPG's --
Morrowwind -- It is kind of old. I have not played it. I heard it was really good though. You could basically go anywhere and do anything.

Fable -- This is a pretty good game, but I would rent it rather than purchase it. It is fairly short, and I almost passed it (I think) in 3 or 6 days (can't remember). The selling point of this game is every choice you make, affects your standing in the world and how people percieve you. So if you decide to be an evil bas**rd, people may or may not pay attention to you.

Prince of Persia -- While I have never played a game from this series, the new one "Warrior Within" looks really good.

Hope that helps.