Hmm, there is a bit of confusion in this thread that I feel still hasn't been dealt with.
To put it simply:
I use WoW, MS Office, DVD Studio Pro and Adobe CS. I have about 500MB of mail, and several GB of photos and music in iPhoto and iTunes.
If I go Archive and Install, can I think start using those apps, browse photos, use iTunes etc, straight away?
Or do I have to find all my installer discs and reinstall everything?
You can use it all straight away.