Agreed, I think the important thing is raising quality across the board. Two possible solutions: a) stop people voting for crap b) get the community to filter out crap.

I don't have any good ideas for option a), and I dislike reddit-style downvoting for option b) since it has the same problem of people upvoting bad stuff, just in reverse.

One idea which could work for b) is a digg-like 'bury' option (i.e. a 'this is crap' button) - but only in tandem with a high karma minimum for being allowed to use it, and some statistical cleverness for deciding when a post should be buried. But I'm terribly enthused with this idea either.