Enjoy your Xbox 360. 
I've finished over 20 games on mine and im still finding cool games in the back catalogue after more than one year of ownership. Renting games is da bomb! I wish everyone enjoyed Halo like I do, but like every game theres a matter of taste to think about.
You should consider going online and purchasing a few Xbox Live games! Here are some games I have now or will buy very shortly online.
1. Castle Crashers!!!
2. Braid
Will buy very soon...
3. Carnan (Whatever) lol its a strategy tile placing game, looks V.cool.
4. Psychonaughts.
5. Jade Empire.
6. Fable 1.
Btw, you should have a look at the back catalogue of very cheap games. You can find some pretty awesome little gems there. Theres a list of games made by Mrstickball which you should look at stickied in these forums so I think you should check it out.
Tease.
