I recently sold all of my playstation 2 stuff for an xbox 360. Im almost done purchasing everything. I just need a little bit of help. I am definitly getting Modern Warfare 2. I can get two other games. I was going to get BFBC2 but i felt it might be too similar to MW2. I would prefer games of different genres. Maybe a sports game, or an rpg; idk. I have xbox live for a year so a game with good online also helps. I refuse to get either gears of war, fallout and fable. I am open to any suggestions so please help me.

Get Gears 2.

Mass Effect 2 is probably an obvious choice. 
Also, which version of Xbox are you getting? Because I would probably put the extra money into the Elite if you weren't already going to.

The 120gig is all your able to buy now, aside from special edition bundles with the bigger 250 in it. 
If I recall correctly...

Bioshock 1 is a great game for only $20.  Resident evil 5 is really good and I think you can get it for $30 now, and then there is always the Left 4 Dead games that are fun.  For DLC you should pick up Splosion Man its really fun.

" @Burns098356GX: Except for the Aracde, the one that doesn't have a hard drive and is $100 dollars cheaper. "

"Burns, ur an ass =). I am getting the arcade because i already have an hdd. Bioshock's not my type of game, ive tried it. Resident Evil was way up on my list but i'd rather not get two zomebie games. RE5 or LFD2? Which one is better online? "

get resident evil 5, it is just a game that i like because it doesn't require so much co-op compared to left 4 dead 2.

Personally I would get either:
Borderlands or Final Fantasy 13 or Mass Effect 1/2 for an RPG
NBA 2K10 or Madden for a sports game.

" I recently sold all of my playstation 2 stuff for an xbox 360.

Borderlands and Gears of War 2.

If you're getting MW2 I would pass on Battlefield for now because it would be hard to enjoy both at the same time, but definitely get Battlefield at some point. ME2 and Borderlands would both be great games to pick up, Forza Motorsport 3 or DiRT 2 would both be worthwhile racing games to get, as for sports games I hear the newest Madden and Fifa games are both awesome but I wouldn't know, and you should definitely get Rock Band. Cause it's amazing, nuff said. Enjoy the 360!

Crackdown.  It's one of the 360 games that's actually fun.  I've just got a ps2 and it's a lot more joyful than the 360.

What genres do you like?

Mass Effect 2 all the way, best game of the year so far. Really, you will not be disappointed. You should get the first one too, they're both amazing games.

Dead Rising.

It's hard to tell since you didn't tell us what you're into.  I would recommend ME2, Forza 3, FIFA 10, and plenty of other titles.  There are so many great games to get.

I would get Mass Effect 1 before getting 2. The story is worth knowing. Also, Bioshock is great. There is also GTA4 if you want an open-world game.

Other people must have said this, but you must get Batman Arkham Asylum, simply the best superhero game ever.  Bayonetta is also good, if you're into that kind of thing...