I find that my touchpad's palm detection is pretty awful. I have set it to the minimum sensitivity not ruining my touchpad use (PalmMinWidth=5, PalmMinZ=1), and I still get random bumps whenever I type on my keyboard.
I'd rather use palm detection than disable keyboard while typing because I find that the keyboard is disabled for too long a period (i.e., I'm done typing and I have to wait 2 seconds before using the keyboard again, which is annoying). A possible strategy would be to reduce this delay, although I'm not sure if the touchpad would stay usable (if you know how to do this, post it, better than nothing :).
Whenever I use windows, I find I'm not having so much trouble with the touchpad, so there must be a way to improve palm detection?
Lastly, I'm running Debian testing 64 bits on linux kernel 3.2.0-rc7.