If you removed the "Who's Online" link from the text menu... you could put the list of Who's online on every page. I personally think that'd be cool... .then you'd always know who's online (not just on the list of forums) as I'm addicted to watching "who's online". You'd always have a recent refresh whether you were replying to a post, reading a PM, or viewing a post etc... the whole list of who's online could always be at the top.
Or would having that on every page add to many queries?