For me, if its 5+ PR I skip it, anywhere on the top 10 no questions asked... unless its a YTube video then you need to ask if they are looking for the video or actual information. If its a PR4 you need to see how strong of a 4 it is, if it has the keyword EXACT match in the URL somewhere, whole not fragmented, and in the title, then its probably a strong PR4, so I would move on... unless under special circumstances.
Goal is PR3 and lowers, all top 10, then you know its going to be easy to dominate in a timely manner.