Comment on Duplicate Content and Canonical URLs by Mark.
Do you think it is a bad idea to remove categories from the sidebar? The reason I ask is, Google Panda negative points, I think, is looking for a template set up. If I have my categories in all my sidebars or footers this looks means more less unique links on every page of my website, same anchor text same thing.
In contrast removing as many redundant links each page looks more unique, which is a good think.
Pagerank could be distributed with either a site map (two clicks) or inter post links that have the category link in them.