In the simplest language: if you don't need an Xbox to play a given game, it's not an Xbox "exclusive."
I really don't see what the debate is there.
As for ME2, the only reason I'd buy the Xbox version over the Windows version is if I wanted to port my game saves over.
Valid reason, but I'd still rather play ME2 on a gaming PC on the big screen at 1920x1080/60fps+ from the couch, with either an Xbox controller or M/KB; whichever I felt like. That's if I even bother to get the game at all.
The Xbox will just have to wait for Alan Wake.