I installed Ubuntu on a Dell E520, and the installation went quite smoothly. I had to struggle to get the proper drivers for nvidia and the screen resolution of 1920x1200 on the 24 inch Dell screen. Nvidia drivers were quite easy to get going once I found envy and beryl installation was even easier.
The friend I installed it for liked it, but he has been having problems with random crashes. I'll be trying to debug the problem soon.