Those of us who ran out to buy the newest version of Mac OS X 10.5 Leopard this weekend had a choice: piggyback the upgrade on top of your current installation of Tiger and keep all your data and applications, or wipe the hard drive and start sparkly clean and fresh (but without any apps or data). As a Windows user, I tend towards a clean install, but Mac commentator John Gruber says:
Arguments that there is something mysteriously dangerous or deficient about the default upgrade procedure—and that you should do a clean install instead, followed by tedious hours manually migrating software and data and preferences from your old installation—are voodoo.
For You Clean Installation Paranoids: Pre-Start Checklist
If you are planning to do a clean install, make sure you mirror your Mac's boot disk on an external drive. If you've got a Boot Camp partition and you're really anal, run that sucker through Winclone first. Before you install Leopard, disconnect all your external drives.
It's also a help to jot a quick inventory of your most important applications, and make sure you back up their preferences (like your TextExpander snippets) or Firefox profile. To be super safe, download all the apps you'll need to reinstall before you wipe your hard drive, and make sure you've got all the discs you need to reinstall the non-downloads, like Microsoft Office or Photoshop. Much to my chagrin, after my clean Leopard installation, the Quicksilver download site was MIA, and lack of Quicksilver seriously cramps my style. Like Gruber, I also believe in Murphy's Law. With good reason.
How did your Leopard installation go? Let us know in the comments.