ZydoSEO - 2:42 pm on Aug 4, 2012 (gmt 0)
What about the most basic, most obvious requirement?
a site where your targeted audience "hangs out" or frequents online?
regardless of PR, domain age, etc.
I've been using this technique recently for picking targeted link placements, and the results have been remarkable. Not only do these sites almost always turn out to be great for improving rankings, but they also drive a LOT of referrer traffic.