I've hated my personal site's theme for a couple of years now. Cleaning it up has been sitting a few items down on my todo list for a long time, and I finally decided to stop waiting for a good time and just move it up the stack this week.
I tried out a couple of starter Drupal themes (Ninesixty and Blueprint) but found them light on documentation and simply not as "complete" as my stand-by on nearly every site, Zen. I was adventurous and went for the 6.x-2.x-dev version of Zen, which has some really nice changes under the hood. The dev branch's documentation still needs some updating, but my familiarity with the theme helped me quickly overcome any issues I encountered.
My main goal with the new theme was to get a more clean, readable, and more timeless look. I essentially don't want to have to update my site's theme anymore... at least, not unless one of my far-more-talented-than-me graphic designer friends want to help me out with it. *wink-wink* *nudge-nudge*
I'll be going through old posts and cleaning them up as-needed to make everything fit within the new size restrictions, but that may take a few days.