Like this:

#tagcloud { height: 0%; width: 0%; }

That's about the proper scale.

I think the simple approach of raising the threshold works pretty well. Spend time improving the metric used by the threshold -- make that part smart. Think about how the reddit home page works, where there's a similar problem: too many good links.

Here's a technique using power law distributions: http://thraxil.com/users/anders/posts/2005/12/13/scaling-tag-clouds