have always thought that getting a link to your blog from a relevant (similar subject area) .edu or .gov site with a high Google PageRank could help search engine rankings. The reason being that links from other blogs or websites, especially those with a higher PageRank, determine the importance of a blog or website. That importance and proper indexing of content drives search engine performance.
Jill Whalen over at HighRankings says she has seen no evidence that having links from .edu and .gov sites is better than other links. However, she points out in her latest newsletter that there’s an interesting debate (5 pages’ worth) in the HighRankings Forum which makes for an interesting read on the value of .Edu and .Gov links to blogs and websites.