After experiments on many other places, I'd suggest that best place to find developers (the kind our startup wants, anyway) is this site. On the 1st of the month, a bot named whoishiring (http://news.ycombinator.com/submitted?id=whoishiring) posts "who is hiring?" and "looking for freelancers" posts in which I put my companies (http://feefighters.com) needs.

Posting on there has led to many good candidates for us. Also check out angelist jobs if you haven't. Both of these methods are free and have led to good candidates for us.