I am a huge fan of OptiLink, and a new web site I found called LinkTree.
Linktree is totally free. It allows you to find topical hubs by looking at who is linking at your competitors and not linking to you. You must enter at least 2 competing sites and then your own. Any time a page links to 2 or more competing sites and not your own it will return results.
http://www.linktree.info
I did a quick review of linktree on this page
http://www.seobook.com/archives/000171.shtml