Good games for good prices?

I got around 30 bucks. I want a good lasting game perferably mutiplayer (online) and M games usually are better so probably M or T. I love shooter games like COD Black Ops and other games with action and adventure. NO rockstar games. Games I already have is COD Black Ops, Dead Space, Sims 3, Dj Hero 2, Madden 9, Madden 10, Modern Warfare 2, World at War, Halo Reach, Medal of Honor. I could probably get a game for 0 to 35 dollars maybe a couple dollars over. I have been thinking about Bad Company 2. Any other ideas would be helpful i would like the game not to be older than 2009 cause older games are'nt usually good. Oh yeah, the only system I have is the Xbox 360...not kinect. Thanks