My site. Still in development, but active. We are pretty eclectic. Join us dammit. :)

EDIT: A bit more info: I built Hubski for the very same reasons: I wanted it to exist. The model is a bit different than HN, as you can follow people and tags, and with the next few updates it is going to be even a bit more so.

But yes, I do think an intelligent general social aggregator is possible and needed. I hope you'll join us. We've just a couple hundred users so far, but the content and discussions we do have are surprisingly quality.