I have HQ and Clamp for Texture Filtering. Looks great and performs great too.
Some games may not be that much sensitive to this setting. However, games that have high quality textures difference may be more noticeable. On High Performance textures look more like mushy and smudged out, especially in distance but on HQ they look more crisp.
Check out here the images:
http://www.tweakguides.com/NVFORCE_7.html
Btw, this is a really good guide for NVIDIA Control Panel settings. Explains everything in details.