I recently bought my gtx 570 and love it does everything I want (havent tested very demanding games just yet) and I was wandering is there any game out there that I would have to overclock it
If you're getting above 60fps minimum then obviously there's no point (unless you have a 120Hz monitor). But if you do experience slowdowns in games then it's well worth giving overclocking a shot.
But it's really a last-ditch effort. I agree with what slh28 said above. OCing it just to get a few FPS or (no offense) pull off a feat could end up in more mess to deal with than laggy FPS.