I used to use the original X ThinkPad, but moved to a 667 15" PowerBook 2+ years ago. Have now moved everything to Apple.
Travel: a 1.5 15" PB 1.25 gig with VPC for one Win App since April.
Office: The PB with a 23" Aluminum display
Home: G5 20" iMac with 1 gig & 250 GB HD - a month old and glorious
Wife: 12" iBook, 1GHz, maxed out
Airport at home and AirPort Express for travel. 40GB iPod for backup on business trips and 20 iPod for wife.