Well....try this test: Set any PC game(HL2,doom3,quake,ect..)you have to run at 30fps(max detail,ect...), now set the game to run 60fps(adjust resolution, affects water quality, ect...)
I think the majority of gamers want 60+ frames per second.....but I could be wrong.
oh, don't get me wrong the more fps (stably) the better!