Local (Denver) company that the LUGs and Ubuntu groups speak highly of.
They have [link|http://system76.com/index.php/cPath/2_52|this mini chassis system] starting at $599 and [link|http://system76.com/index.php/cPath/2_6|mid-tower chassis system] starting at $399 - all systems come with ubuntu preinstalled - no M$ tax.