Colin OOOD said:Go for a Centrino. No question. Clock speed may be low, but the work differently to P4 chips and my Centrino 1.7GHz laptop is roughly on a par with a 2.8GHz P4. In addition, their power consumption is much lower than the P4, which means much quieter operation as there's less heat to dissipate, and battery life kicks the shit out of any P4 you care to name. Occasionally at gigs I get earth-loop problems with my soundcard, and generally cure it by unplugging the laptop from the mains. I have absolutely no fear about running the laptop off the battery for the whole set. They're also thinner and lighter than the P4.
My advice to you would be to go for at least a 2GHz Centrino. You won't regret it. I got mine from http://www.nusystems.co.uk - this is the one I have: http://www.nusystems.co.uk/buy.asp?p=0&g=57&b=11