just pick a soft fabric one, but NO plastic coating! i used that mousepad as a frisbee once(long story) and the plastic shatered but was still attached to the base so, it cut my wrists and I bleeded all over it.
and if you don't set the sensativity high on your mouse, get a big mousepad.
also square pads are cooler! and your not tempted to use it as a frisbee...