+1 for Linux Mint, but they don't ship it to you. Also, the gnome desktop will be a teensie weensie bit heavier than Xubuntu. On the current config, playing HD movies (above 720p) will be a little buggy, if it plays at all. Although Mint gives you codecs out of the box, Ubuntu 9.10 is not as painful as it used to be. There will be a prompt on your first login to install restricted formats, and that's that.
Also, if you are comfortable with programming, think of either Arch or Slackware. Not too hard, really, and not too painful either. Slackware gives you codecs out of the box too. Arch has rolling updates, if you plant to use the setup for a long time.
If all of this is confusing you, then just go for Mint.