If the game is 30 fps without any frame drop at all, then the experience feels really smooth. As long as the frame rate is locked at a multiple of 30, then it's really good to the eye.
I'm playing Wind Waker right now, and even if it's locked at 30 fps, it feels really, really smooth.
60 fps is good when timing is essential, like in fighting games and FPS games. But for third person games like infamous or Uncharted, locked 30fps is more than enough.







