domain name and directory structure

which is better...does it make a difference?

[rrl]

I'm testing out placing my client's websites inside of mine. I've noticed that when I announce that their site is released and I include some of their keywords in the announcement, my site ranks high, often higher, than theirs.

So, it got me thinking that maybe I should be nesting sites inside of mine.

Anyway, if I do this (tell me if this is a bad idea), am I better off using 'www.domainname.com/nestedsite' or 'nestedsite.domainname.com'. Does it matter? Will the latter be treated as a separate domain name?

Regarding site structure, I have a links page to all of my sites that google updates regularly and I'll have the nested sites linked to from there as well as my home page. Thanks!

[rrl]

Incidentally, all of my sites have the same general theme.

[rrl]

Just an update on this, the subsite ranks pretty well except for one phrase, which ranks #8. It inherited the main site's PR minus 1.5 or so. If I want to move the site to its own domain, what redirect works best with Google?