Alright you wp blog gurus....
 

Is it better to use one domain and toss a bunch of subdomains with wordpress around or use a bunch of separate domains at the root?

I personally use a single domain for each blog.

I do both, but the single domains tend to do better. In some cases I have a sub-domain blog that does better than the others - but that's more a matter of the amount of handwritten content I have on it.

Seperate domains for sure.

+1 for this, especially if done on a big scale