Well maybe I haven't been playing too many hardware demanding games. In Mass Effect 3 with 2x SGSSAA I've been getting a constant 60fps during gameplay sections, only dipping to 45-55 during some cutscenes. It's a good balance between IQ and frame rate for me.
But let's say I did want to up my IQ at the cost of frame rate, what's the best way to limit the frame rate? Use the new Nvidia frame rate limiter set to 30fps? Force 1/2 Vsync? I hate screen tearing too so I usually use Vsync+Triple Buffering to limit my games at 60fps.
I have a pretty average PC, so I usually lock my framerate at 30. I've found that using D3DOverrider (for v-sync + triple buffering) on top of Bandicam (which contains the FPS capper) works well 99% of the time.
Some games have trouble recognising Bandicam but usually quitting Bandicam and restarting it while the game is running will fix it. A few games will ignore D3DOverrider while the 30fps cap is on so you'll get tearing then. I'm not really sure how to fix that other than simply using in-game v-sync with the cap.
Also, Bandicam takes video and screenshots in high quality, so if you're into that it's a pretty nice little program.