120Hz HDTVs and 120Hz PC monitors operates differently. Much differently.
120Hz HDTVs (240Hz a well) does internal video processing to improve smoothness and movies / videos the "live" look. Frames are created and inserted between every two actual frames from the single DVI-D or HDMI connection which only operates @ 60Hz. This will cause input lag in games. The "refresh output" will still be 60Hz.
Yes, you "can" use it with any 120Hz HDTV out there, but you're gonna headaches sooner rather than later.