You might want to take a look at http://elementaryos.org/ (it's based on ubuntu too, so almost everything will just work the same). Not stable yet though.
As opposed to e.g. CrunchBang (desktop-wise) or Arch (system/packages)...
The clincher for ubuntu over others, for me, has been the community support - it is such an active community googling ubuntu and your issue usually finds you effective answers in minutes; not always so easy on some of the other ones.
But on HN, I'm sure 'them's fightin' words'.
You might also like xubuntu or linux mint xfce. They use the lighter weight desktop environments xfce.
For vps/server I prefer centos/debian.
edit: also wanted to add that crunchbang has run much faster for me than lubuntu which I previously was using. Generally ~200-250mb ram, boots extremely quick as well. It will run great on an old junk pc, or a new workstation.