So many people on these forums are bent on erasing their drives before they install Mac OS X 10.5 Leopard. I want to know why. Don't you think Apple has made Mac OS X Leopard smart enough to upgrade and be just as fast as a clean install? I mean... if you're keeping your computer organized and don't download meaningless 3rd party apps and watching what you're doing, then an upgrade should be just fine right? Here's what I may do. Backup my entire Tiger drive onto another drive, then upgrade install directly on top of my current Tiger drive... this way, if I do run into problems for some reason (don't think I will), I could always just go back and start over. The computers at work are upgraded and upgraded over years and years with new software and I've never ever erased the drive and started over fresh. It still runs great.