Best way to start over and do a fresh upgrade?

Hey everyone.

I've upgraded to 6 from 5 and things just aren't going as smooth as I would like. I won't go into detail but its just a mess! (Its also running slow as hell).

What I would like to do is trash my site, start over and re-import all my content and images from my v5 site into the new lovely clean database and ftp all my images back up.

What's the best way to do this? I've already spent a day working on the upgrade (which I am about to roll back) so any simple tips would be great :)