Okay I bought an external HDD. Problem is that it is quite loud. So I would like to turn it off when I’m not using it. The prefered situation is to copy my media and important user files to it, then do a clean install of OSX 10.4 on my internal HDD. But what are the important folders to copy so I can get all of my accounts back to the way they should be? This should be an easy question to answer, but my google skills aren’t helping, and I’ve seen it somewhere before.
I’m a bit confused about your goal here as far as backing up your files and the clean Tiger install. As long as you have the space, why not just clone the drive using Carbon Copy Cloner or make an image w/ Disk Utility?
I haven’t used it (don’t have 10.4) but it appears the Setup/Migration Assistant is what you want.
The stuff you really need to copy is your users folder, whatever NetInfo stuff is needed, and your apps (which, if they’re nicely written, will be packages and store their settings in your user Library). If you have a need to run OS 9 or some Classic apps, there may be some more work involved. Hopefully you can reinstall the apps in the worst case.
It is definitely best to make a complete backup of your current drive. And if you don’t already have another backup drive, I’d recommend partitioning your external with one the same size as your existing, and make that a regular backup destination (better than nothing).