I've had the good fortune to set Ubuntu 8.10 and 9.04 on a Dell D610 - works brilliantly, with reasonable control over almost everything. The one thing that doesn't work is, of course, Skype - the camera drivers aren't playing nice. But that's a relatively minor annoyance. It also has closed-source wireless card drivers (Broadcom 4318) but fwcutter does a very good job of detecting and auto-installing the card while the machine is on and connected to the wired network.

I'm quite pleased with it.