
It looks like Django is bigger and stable, while Flash is smaller but growing.
There's work on web-sockets and stuff for Django, so it's capable of making modern websites. But I don't have a time machine to see whether that causes massive hype or is largely ignored - you'll have to do your own extrapolation for to the near future.
(I didn't include Javascript ones because "nodejs" is not a webframework, "express" is a common English word and no one seems to search "express.js")