[Gritz]

3 guildies have had trouble with ibuypower machines in the past (connections loose, DOA components, cracked case, if I recall correctly) - if you are comfortable taking a PC apart and checking connections and general troubleshooting, then you should be fine. If not, I'd stay away. (Yes, a sample size of 3 is not very big, but I've heard more negative about ibuypower than tigerdirect/newegg combined).

Edit: In regards to Ubuntu - stay away unless you are a hobbyist or IT professional (or want to become one). Google 'linux live cd' to try out linux without installing. I have an Ubuntu install on my MBP (via Fusion), but I can't find anything that is easier/faster on Linux than XP/Vista/OSX (the other 3 OSs on my machine).