No need really.
I have done both on different system:
1. A clean install for my PB G3 500 laptop - thought I'd see how the base system ran, and add apps and such subsequently. I clean installed this machine with 10.3 a while ago (Over a year)
2. An upgrade install on a 1GHz G4 iMac (17"). This machine came with 10.2 about 2.5 years ago, and I haven't clean installed it ever.
The problem with archive and install is the physical location of the system folders on the HD, but as OS X defrags "on the fly" the speed difference shouldn't be too noticeable.
I may have clean installed on the iMac, but am in the middle of a project, and don't have an adequate backup system. I still may do it to get rid of 2.5 years of crap on there, and just re-install the things I want. (I'm worried for my calendars etc though, with my Palm Pilot and stuff.)
For a 1 month old machine, I WOULD do a clean install, if there's nothing critical to lose (like iTM folders). It gives you the perfect opportunity to do everything the way you should have the first time
Here's a criteria I would use:
<4GB Home Folder: Backup Home to DVD (or otherwise) and Clean install. (You may also want to back up the App folder)
It's amazing the stuff you find in your backups that you look at and then think "I don't need that, why did I even have it?"
I reckon a clean install of my iMac, and then putting back the stuff I want would gain me AT LEAST 10-15GB of space!
Remember too, that a lot of apps will have a Tiger update soon, so as long as you can remember the ones you use and pay for (make a list etc.) you can get the new ones as they appear!
There are definite benefits to both. Depends how Virgoan you are!
