Aside from .gov and .edu. I know gurus will tell that .gov and .edu are useful. So aside from links from authority site what kinds of links are useful nowadays to be successful in SERP.
yea i find links from relevant sites/blogs, regardless of their PR, produce very good results. 1 good link from a related blog can deliver more than 100 directory submissions.
Links from Web 2.0 websites are also known as authority sites. That is why people can get their Squidoo lenses on top of the Search Engines quite fast.