I've had my xbox for 9 months, and I honestly have only 5 games for it. :lol: I actually bought 4 of them all at once, and the other one after a friend bothered me to buy it. But I recommend all of them.
They would be Red Dead Redemption, Dragon Age: Origins, Call of Duty: Modern Warfare 2, Assasins Creed 2, and Left 4 Dead.

Red Dead Redemption is a great game, it actually takes place where I live, only awhile back. Haha. The storyline is AWESOME and took awhile to finish it, though the achievements are a pain in the neck to get. I spent hours just riding around on my horse because I was uber excited about it. XD The gameplay takes awhile, and the mission aren't too hard. There's a TON of extra content like minigames, side quests, and even hunting. 8D There was only a couple of mission I had to redo, and it was because I was doing something wrong and I felt like a dumbbutt afterwards. TBH, I think rockstar was better suited for the wild west, than for games like GTA. The graphics rocked, and all the little details blew my mind. 8D

Dragon Age: Origins, (I also have the EP for this, don't start out on the EP though) this game is also awesome, if you're into RPG's. BioWare put a LOT of work into the game, I love how the actions you use in game effect everything! The only complaint I have is just the amount of repetetiveness. Get a quest: kill tons of stuff, get item for quest. Get new quest! Kill bunch of stuff, finish quest. Etc. But the different parts of it were just amazing, you can pick an "origin" like dwarf, elf, or human. and different factions of those too. And you start at a different place for whatever you choose. Like, noble dward, common dwarf, etc. I really liked this game but I had to take a break in the middle because it just got so long! I have close to 70 hours of sheer game play on it, mainly quests. And the ending is so awesome. u_u

Call of Duty: Modern Warefare 2, I've never played CoD before and this game made me love FPS games. 8D The storyline was awesome, the missions weren't easy but they weren't horrible, especially on veteran. u_u. Again, I can't stress how AWESOME the storyline was! I got so mad... about ghost! No spoilers though! xD Multiplayer also rocks, if you're a female don't be afraid to go on mic. It's fun to be mean to guys, if they harass you just be a b**** back to them. ;) Once you find a party to play with though, it gets REALLY fun. And it also has spec-ops which you can do singleplayer, with a friend on a second controller, or online. Some of those missions are hard though! Dx

Assassins Creed 2: Amazing Graphics, though I was kinda lost since I skipped the first one. The controls were kinda hard to get used to after played CoD so much though. :lol: But the storyline is amazing, and I love how you can continue playing after you finish it. Some games don't let you do that. /coughdragonagecough/ Basically, you're a guy who's going against an evil agency, and you're able to go back to the past and become someone in it (with some kind of technology) so you become an assassin, and go through his life so you can "learn" all of his cool tricks to use as your original person. Which sounds weird/crazy but the game is awesome! It's in the 1400s in venice and the graphics are just.. :drool: You actually feel like you're there.

Left 4 Dead: 3 words: kick zombie ass.

Sorry if this was too long or anything. 8D but all these games are so great u_u and I love that I haven't had to actually buy any more games to keep me entertained. hehe.