I've only ever owned two laptop computers in my life.
My first was an Apple PowerBook 1400. It was a boat of a laptop -- heavy, clunky feeling, small screen -- and it ran System 7.5. I bought it so that I could have one foot in the work of the Mac, but it didn't do too much to win me over. Unfortunately, of course, I was about 4 years too early: it wasn't until 2000 that Apple's laptops got light, fast and sexy.
My current laptop is an iBook Late 2001, a model name that belies the fact that Apple hasn't really figured out how to differentiate their products from each other now that they've stopped using model numbers. The iBook is so completely different than my original PowerBook as to be almost a member of a different medium: it's fast, light, has a large, bright screen, and it runs the latest, greatest versions of Mac OS X.
I cart the iBook with me to Yankee, where it becomes my main working machine for 4 or 5 weeks out of the year. I took it to France with me when we visited for a month in the spring of 2005, and again to Denmark for the reboot 7.0 conference. When I'm at home, I use it to work in my various WiFi-enabled haunts, like the Formosa Tea House, Timothy's and Mavor's. I also bring it home with me to let me watch video that I've grabbed from the net on our home television.