I use an OEM microsoft natural keyboard. Looks a lot like that wireless pro one, but it's white/blue instead of black/silver. The feel of it is great, and it almost makes me want to get rid of my logitech elite at home. I've sworn for years that I hated the natural keyboards, and they felt extremely odd to me. So I get a new job, and my computer has one on it. Well I have other keyboards I can swap out, but I'm like what the hell, I'll give it some time. Within a few days of it, I like it a lot. It honestly is just a more comfortable position for you hands/arms. I can see people that type with one hand very often not liking it at all though, because of the split and angle.
As for the pictures that Simguy posted, I have to agree that you need to watch out for the ones with the frigged up arrow keys. the ones with the arrow keys all bunched up like a cross instead of the tetris piece design. i hate those arrow keys with a passion, can't even tell you how often those things make me miss what i'm trying to do.
All in all, if I had cash to blow right now I would go with one of the wireless natural pro's. I currently use a logitech elite wireless and it's been great, the only complaint i have with it is it's not as comfortable to type on as this natural that i'm used to at work now.
One thing I will say about these newer keyboards though, the F-Lock is extremely annoying. Why on earth would you have to re-set the f-lock every time the computer boots. Not only that, to make it more annoying the pause/break key only work as pause break when the f-lock isn't on. extremely annoying to me.