HTC Tilt 8925 / TyTN II
Case for this phone
The screen protector does not seem to interfere with use of the touch screen in any significant way. The only time I even notice it is when using scroll bars at the very edge of the screen where the screen protector ends, but even then I'm really only noticing the cosmetic difference at the edge than any change in performance.
I'm pretty careful with my phone, but it is pretty much completely undamaged/unscratched so far.