I'm using OctoPart dozens of times each day to check availability, pricing, specs, datasheets etc. However, I sometimes look for "popular parts", either when specs aren't that special or as a starting point to find suitable components. I know that "popular" is pretty vague, but is there any component search engine that has some kind of useful ranking other than price or the "relevance" sorting OctoPart does? I want to use common parts when possible, to ensure low price and good sourceability.
Try ECIA Authorized.
You can get a pretty good idea of what's popular by who carries what and how many they have on hand.