Notebooks (Business Lines)
1. IBM/Lenovo T & X series
2. Dell Latitude
3. Panasonic Toughbooks
4. HP NC line

Notebooks (Consumer)
1. Dell 6X0m
2. Apple MacBook
3. HP/Compaq dv2000/v3000

Not much opinion on desktops as I usually build my own, but Dell's seem
to be decent (only issues I've seen are bad caps which they replaced).

Similar here.
Notebooks (business class, not home - e.g. latitudes!)
1) IBM T41,42, 43 or X31, 40)
2) Lenovo Thinkpads - jury still out. Early probs with cheap plastics
and dodgy dock fitment seem rectified though. Not sure if they'll keep
up the world-class support and drivers though.
3) HP NC's are good
4) Dell Latitudes are good, although nothing beats the old CPiX's!

For home laptops, the Macbook isn't in there. Terrible quality control
on a lot, and I have one. random shutdowns, discolouring plastics,
appalling thermal paste misuse on some, blocked fan vents etc. When
they're good, they're very very good, but when they're bad they're
horrid...

Corporate Desktops:
1) IBM M51, M2, S1 and S52. Bulletproof, reliable, tool-free and
everything a good corp desktop should be
2) Fujitsu Siemens still make some that are built like the old days
with metal chassis etc...
3) Dell

ric