For me upper 30s/lower 40s is just fine, but then that may be because I'm almost always behind where hardware upgrades are concerned. *shrug* That said, i do know what a steady 60 looks like and anything beyond that is just overkill as far as I'm concerned.

It's kind of weird that I see a good few older games that'll allow me to set my own capped framerate, but with newer ones there's only a tick for the generic vsync (if at all).