I've had a Dell Latitude x200 for 5 years and it has been extremely reliable. It has survived well over 100 business trips and about 500 passages through airport scanners and has been in daily use....
I upgraded the memory as it was struggling a bit with some recent applications, but now its fine.
Dell Customer Service were pretty good - they had it repaired within a couple of days after I managed to drive over my briefcase and broke the screen....
They also sent me a replacement keypad under warranty a couple of years later as some of the keys had stopped working - probably a legacy of the earlier event.
When I told them how happy I was, and that it was a shame that they hadn't given me as good service with my earlier Latitude LT (far too fragile), they tried to repair it, but killed it....
After 'robust debate' and a personal letter by recorded delivery to their head office, they then gave me a new Latitude X400 with Office 2003 included!