[dnanian]

Hi, DA.

Yes, a full "Backup - all files" backs up your applications, your Mail, etc. Copy Protected applications (Photoshop, for example) might notice that your system is different if you do a full reinstall, so be aware of that.

A new OS might screw up applications that aren't compatible with it, of course.

I generally wouldn't recommend a clean install. Rather, I'd do a full backup of Tiger -- then TEST the backup. Once you're happy, disconnect the backup drive and put it aside.

Then, do an upgrade install of Leopard. If things are working well, you're all set!