Move a WordPress MS site to a standalone Wp install

I've been looking at the various forums on this one, and there does not seem to be a consensus, so I'm submitting a forum request here.

My client has a could of sites in the mulit site install that they would like to extract and run on stand alon servers for performance reasons.

What's the best way to get the site (not just posts and pages but plugin and theme data too) out of MS and into a standalone site

Thanks

Neil Matthews