Tiger: Upgrade, Archive and Install, or Clean Install?

Tiger is coming, and I'm ever so excited. Every time Apple comes out with a new up date to OS X I become less and less focused on the real world and more and more focused on what the new Intro video and accompanying music are like.

A few days ago C.K. wanted to know what voodoo you do before you install a major OS rev, like Tiger. What I want to know is installation method do you use? Are you a nuke and paver? Or do you prefer the Upgrade route? Perhaps you archive and install (the best, or worst, of both worlds)?

I typically just upgrade (after I back up my data, of course), but I am open to suggestions and if I know anything about you, our dear readers, you're a suggestive lot!