I started out (against the advice of others) with the cheap button triggers. They don't work. I then tried the ddrum redshots and they work better. I used an Alesis DM5 for the sound module. I have a friend who really likes the ddrum module and has used audio tracks to trigger it as well. But for replacing drums in an existing audio track, I got rid of the triggers and modules and bought drumagog instead. For $149 you really can't beat it. see
www.drumagog.com