Snow Leopard: what do I need to back up?

I’m going to do a wipe and install in order to clean up the cruft that has accumulated in my Mac. I have a Time Machine backup, but I don’t want to restore everything, just my pics & docs, music, Keychain and app preference files. If I back up only my Home Folder, is that all I need? Is there anything to be aware of, as far as restoring the Keychain, Safari bookmarks, iTunes library, etc.?

I have been googling, but can’t find anything directly related. Thanks for any insight and/or links.