To find interesting stuff I mostly use aggregators like HN, MetaFilter, Reddit, etc, and from there I populate my RSS feed to keep track of the good stuff. Can't forget Wikipedia.
Of course other media (such as newspapers, magazines, books, radio shows, etc) has a lot of interesting stuff, and then of course other people knows a lot of interesting things, so if I get an interest on a thing I can start some search on a subject, but if you don't have a specific query in mind, I agree that search engines give weak results.
Interesting question, I hope you get more answers!