I have yet to have a problem with compatibility with my 360. Though it is true not all game are backwards compatible for the console, they tried to do it for most of its popular games. It's a cool feature, but I don't buy new systems to play old games anyways...
arrrgghh....it ****es me off when people buy a brand new 360 and all they play is halo 2 on it....and they just so happen to own the first xbox... X_X
YouTube - Kicked In The Nuts
^
thats what should happen to them O_O