Based on what I've seen, here's my thoughts on laptops:
Exceptional quality: IBM, Apple, Sony
Good Quality: Dell, Toshiba, Fujitsu
Would Never Buy: HP, Compaq, Gateway
...this is based on what I see at work (I manage a staff of student-employees who help students with their personal computers in their dorm rooms). HP and Compaq lose out because of terrible quality of the units--I've seen three-year-old Compaqs with pieces falling off of them--and lousy tech support. I'm particularly sorry to see how far Compaq has fallen; I used to own a Compaq Aero subnote (486 25Mhz) and it lasted for years, terrific case quality, exceptional service and support. HP... well, I'd buy a printer from them anytime, but that's about it!
Hands down for construction, IBM and Apple make the nicest units, but they're either pricy or (in the case of Apple's iBook) well-priced but only an option if you're versed in/willing to change to Mac OS. Sony laptops are wonderful, but _don't_ lose the recovery CD!
Dell laptops are pretty decent, but I've seen some slipshod quality (batteries getting 15 minutes charge after three months and Dell telling the student this is "normal"!) and increasingly-poor tech support. Toshiba and Fujitsu aren't bad, similar in my mind to Dells.