I have been using laptops for five years as the brain to my rig. I currently use a laptop running Sonar 2.0 to run sequences as well as control of a digital mixer and even lights. We even use it to control the guitar players Pod preamp....I also incorporate audio in the sequences for backing tracks as well. additionaly I've been considering using mp3 as a backing track but I still need some real time control over the midi gear from time to time.