Lots of you are mentioning HHKBs. Is this topic only about typing speeds on HHKBs? Is there something about HHKBs that enable people to type unusually fast? Is it possible that the smaller the KB, the faster you can go? I would've thought it the other way around—don't you have to use multi-key shortcuts for everything that was left out? That'd slow me down.
But there's also the adrenaline you'd be getting from typing on such an obviously cool, hip KB. And if you're in an office, there'd be the nervous energy, wondering when the next person was going to stop at your desk and say "Oh, what a cute little keyboard!", or ask you how on earth you can get by with so few keys and expect you to explain it for the nth time. And of course if you had to move your keyboard from place to place as part of your work, having such a smaller, lighter one would leave you with more energy for typing. Yes, I can see how there could be a significant chemical factor here.
Anyway, I average 105. But that's on Dvorak, which may be cheating. But I'm also on buckling springs, so that probably slows me down commensurately. Fortunately, I don't have to move it around—but then, I don't have anyone stopping in my home office asking about it, either. Of course, fewer people would ask about an IBM than an HHKB. It all seems to balance out.