If people are going to say "there's no difference between 60fps and 120fps", always add a "FOR ME" at the end of that, never imply as if it's some kind of wide-accepted fact. Because it's been fucking REPEATEDLY proven time and again that there is absolutely a difference, especially when competitive tournaments like MLG are endorsing 144hz monitors (think they are doing that for giggles?).
As for me, I've been using a 120hz monitor for the past year and now it feels like night and day compared to 60fps. As soon as the framerate dips down to 50-60fps (really intensive scenarios or something) I can immediately tell because it feels so damn choppy. I can tolerate it in games like MMO's during really big boss/world encounters with tons of players on screen (expected really), but can't tolerate it in more fast-paced games like 1st/3rd person shooters...and Audiosurf. 120fps in Audiosurf just feels awesome, period.
30 fps is not even an option at this point. I don't know how anyone can play competitively with that level of added input lag (33ms+) and slideshow-stile camera panning / movement. 50-60fps is my "absolute minimum", 80-90fps+ is my expectation, 110-130fps is my preference.
There is no going back. I am humbly awaiting monitor technology to improve, especially in regards to IPS panels (currently 120/144hz is TN-only @ 1080p). Something has to be done to lower IPS response times and increase refresh rates to 120-144hz while running at 2560x1440 and having splendid colors / viewing-angles.