I retired my G5 in January and swapped everything over to my 15-inch Macbook Pro, the previous core duo version with the express card slot. While it's very convenient to have everything with me all the time, it's nowhere near as fast as a Mac Pro.
However, I am very tempted to get a new 17-inch i7 and use it as my primary machine, hooked up to a big display in the studio, and all by itself on the road. I can get an eSATA card and hook up some big external drives for data and scratch. Hmmm, very tempting. I do note that it only has one FW800 slot, and no FW400 slot -- they could have given me two FW and two USB, which is what I have on my current MBP. Oh well.