The key to linux is making it as painless as possible to re-install. Sad but true. Hopefully one day upgrading from one major dist rev to the next will work, but until them we’ll be forced to live in reality.
The key to this is the partitioning. Some for unknown reason, a lot of people recommend you put /usr or /usr/local on a different partion. Why?! I can understand if it’s a shared system, but we’re talking about people’s home computers. No need for a seperate /usr/local paritation & if you’re one of the rare exceptions that do, odds are you know it already without being told.
I think a better way is a /home partition. In fact, I think most distros should create it for you. That way you can pretty much nuke the OS without harming your personal files, your resource files, etc. As a user, it makes an OS largely transparent.
Having a parition that persists from install to install is pretty nice for other reasons too. You can create /home/install, and every time you install something, you throw the tarball or package in there. (That way you don’t have to go hunting it down again. I find this handy for all thie little window maker dock apps I like, as well as things such as sudo that weren’t always included.)
Most people create /home/cvs, so having /home on a seperate partion saves that as well. (Some will place it in /var, but I think for home systems it’s best to have a clear deliniation between user-stuff & system stuff.)