What games should a new xbox 360 owner pick up?

I'm pretty new to 360 as i've been mainly playing on my ps2 / nintendo ds up until a few weeks ago when I won the 360 in a contest. I'm a major fan of horror & survival horror games and games that have a more darker atmosphere. Aliens & Zombies are a plus. I love FPS but i'm not very good but there's always room for improvement. I do have XBOX live so I am looking for games that still have a lot of online matches. I've already been made aware of Crysis 2, COD and Halo, is there anything else besides those for online? As for single player, I also love RPGs, fighting games, action, platformers, anything but sports. I'm running on a low budget so I can't drop a lot of money on games but I want to buy a few that are really worth it. Any suggestions for me?

EDIT: As of now, I own Bioshock 2(games like that game would be fabulous!), dragon age origins, some kinect games, dead or alive 4, assasins creed, fable 2, and soul calibur 4(which doesn't work so i'll be returning it for something else). my gamer tag is vampyrebats so feel free to add me as well. ^^

:) thanks ahead of time.

Gears of war is a favorite amongst 360 owners (I never liked them though). The new Mortal Kombat is good for a fighting game. If you like RPG's, deffinitly get Mass effect 2. Deus Ex: Human Revolution is looking like a promising RPG, coming out 8/23.

get ALAN WAKE one of the most underated games this gen.

Try the Mass Effect series, great story, great gameplay, great visuals, you get the picture.

Alan Wake.

Castle Crashers on XBLA....and use the Game Recommendation Thread

Dead Space 1 and 2 are absolute musts for survival horror fans. Better than the new Resident Evil and Silent Hill games.

You can find the first one for like $10-20. Awesome game.

Dead Space 1 and 2 are absolute musts for survival horror fans. Better than the new Resident Evil and Silent Hill games.

You can find the first one for like $10-20. Awesome game.

seankane

Lots of series! . try Mass Effect 1 & 2 . GOW series. Oblivion . Bioshock part 1 :D

i highly recomend the Mass Effect Series For awsome gameplay. Also the Gears of War Series. And The Assassins Creed Series. Do not miss out on those. they are big dogs

Based on what you said, these games would suit you.

1. Mass Effect
2. Mass Effect 2
3. Dead Space
4. Dead Space 2
5. Dead Rising 2
6. Resident Evil 5
7. Resident Evil 4 HD
8. Tekken 6
9. Street Fighter IV Arcade Edition
10. Ninja Gaiden II

If I could make only one suggestion I would tell you to get both Mass Effect games. By far the best action RPG's on the system and overall just an amazing experience. Plus, if you do everything there is to do you'll clock in around 40 hours on the first game (give or take depending on difficulty) and around 50 on the second game.