So now in July, I'm upgrading to Ubuntu 9.04 (released in April). To state how much of a laggard I usually am, I think this is the most up-to-date I've ever been on an OS upgrade.
I decided to use the standard "upgrade to 9.04" feature exposed in "Update Manager". So when I saw a screen like this:

then I felt happy. I felt like I knew what was going to happen, and that I was in control of the process to some degree. This freed my mind up and let me think about what I could do to minimize any upgrade risk.
In the past, because of the helpless feeling of being out of control of what's going to happen and what I can expect, I've avoided upgrading until the pain became great enough to justify a full backup/reorg of all my files that I for sure wanted to keep.