I recently bought a HP NC4000 laptop. I am very happy with it, except Blender in XP is really slow. This is due to the fact that has a ATI Mobile Chip in it. However I recently switched and started using XP/Ubuntu(Linux) and Blender in Linux is REALLY fast. Most of the time it seems to run just as fast as my 1.2 Duron with a GeForceFX 5200 PCI in SuSE 8.2.
So, if you have issues with Windows/ATI/OpenGL. Try software rendering in Linux. It worked for me on my 1.4 Pentium M with 1MB Cache, and 512 MB RAM.
BTW, the NC4000 is incredible. All the above at 3.5 lbs. Love this thing…
(End of shameless linux plug)