using chickenfoot in firefox:

//begin include('~/jquery/jquery.js'); b=new Button('hide comment heads', function() { $('.comhead').hide(); }); insert(after('add comment button'), b)); //end

click the new button injected to hide comments. can be automatically triggered whenever ff opens http://news.ycombinator.com/item?id=*

you can make it fancy like toggling instead of hiding, or showing only points or authors, but it's sufficient for me (actually i use auto-hide-trigger-with-no-button which is simpler)