I use a MacBook Pro because it runs Mac OS X and I can run Windows XP and Ubuntu with Parallels. You don't want a Mac, so...
[link|http://www.system76.com|http://www.system76.com] - these guys have Ubuntu laptops with all the bells and whistles and are pretty highly thought of among the local LUGs.
My boss run Ubuntu on a Sony Vaio that he's pretty fond of. Prior to that he had a Toshiba that he liked, too. I can find out model numbers if you're interested in either of those.