The kinesis contoured keyboard is an absolute marvel. Priced like it too, but if you have problems with your wrists it's a godsend.
I actually have one from before they made USB models, a PS/2 one with the Windows key mappings, which kind of sucks (use it with a USB-PS/2 adapter). If and when this one gives out, I know I'll be replacing it with another Kinesis contoured keyboard for sure.