A higher refresh rate does help a little, even if you aren't getting the FPS. However, it won't be at all helpful on an HD TV, when used with a PC, as it won't operate with a PC at 120hz. The main differences, if you actually get a 120hz monitor, is it does refresh twice as fast, which reduces tearing, and decreases latency a tad (most noticeable in mouse tracking). This applies even without 60+ FPS, though the biggest differences do come with higher FPS as well.