I normally save my bookmarks out to a file for my browsers, backup or move important stuff to spare hds, move my steamapps folder to spare drive (saves redownloading 190gb...lol) make sure i have the important stuff like LAN driver handy, and make sure games saves are backed up, then off I go.
Worth mentioning I have all my common drivers and app installers on a 2nd drive beforehand. I used to go down the route of backup of the physical install but it gets out of date or could have backed up something thats corrupted or virused etc so often better to wipe and start fresh with latest updates.