Hi,
I've been using Peizo pick up to detect a drum hit quite successfully. I run the peizo through a small amplifier chip and then read the anaolg signal on the Arduino. I find that looking for a a value above 700 will detect any sort of hit to the drum skin.
I use an LM386 amplifier chip connected directly to the peizo (they're tiny) and then I can run the sensor wire as long as I want.
Let me know if you want further info on this and I can send you some schematics.
Dok.