I've been a huge fan of the 'hot or not' style quick voting for a while now. So much so, that my friend and I included it in a little test project we did a while back: http://beta.popularo.com/

The goal was to circulate new content to all users and at the same time reduce the chances of gaming the system (we were frustrated by the digg "power user" submissions).

Needless to say, it sits dormant now but we're both glad reddit and digg have implemented similar features.