Well, the Ubuntu installation didn't went good after all, so I've just installed OpenSUSE 10.3 (Gnome) instead. It's actually (almost) my first time using OpenSUSE. My first impression is mainly good, but the repeatedly repository caching during package management annoys me big-time. I really hope it's going to be corrected soon.
Besides that, it seems very professional and I look forward to try it a bit more. I've decided to give it a chance since the installation with RAID and all just went smoothly.
