Now I am aware of the purpose of backlinks and how the get you a high PR. My question is what will my site benifeit more from, single sites that link my site or topsites/post your own link sites? What does the search engines recognize more?
More then likely "single sites" as you say, as topsites aren't that great quality for getting a link to your site.
Also topsites have tons of outgoing links and so the PR is divided up accordingly while single sites (if the content is similar to yours) can be a quality backlink with not many outgoing links (hopefully) which is much more important in googles eyes.