The Freetagging capabilities in Drupal 4.7 alone make it worth the upgrade.
Luckily I found this great video tutorial to guide me:
http://ftp.osuosl.org/pub/drupal/files/videocasts/4.7-upgrading.mov
I just need to backup first, then we’ll see what happens.
UPDATE:
Well, I’ve made the update, and so far it’s working just fine. The first thing I did was to go in and change my “tags” taxonomy to use the freetagging option. On little click, and all my current tags were magically transformed from selections from a list to a string of comma separated values. I’m free to tag away!
Now, I need to get my theme and some modules up and running again.