Why update for the sake of updating? I have three bikes with threadless headsets and I'm of the opinion that while they have some advantages, so do threaded set ups, not least of which is easier (in my opinion) headset adjustment, the ability to raise your bars without affecting HS adjustment, and not having to buy a new fork when you've decided that you want the bars higher than the steerer will let you take it. People seemed to have realized this and so threaded gear is not that hard to come by now. Check http://rivbike.com/ for example.

But yeah, I'm sure this is an old debate around here.