Well, I used to use the Microsoft Natural Ergos, I'd pick them up for something like $20 or $25.
Now I use Kinesis Advantages. I've got one for the house, and one for work. I absolutely love them and think that they are worth every penny (a bunch of pennies actually).
I've got one of each. The silver one (the "Pro") comes with a footswitch and extra memory. Both keyboards are programmable (key remapping and macros).

Kinesis makes several keyboards.
Kinesis Ergonomic Computer Keyboards
If you want to peruse some keyboards, go here:
Ergonomic Keyboard and Ergonomic Keyboard Products
I'm also a little weird. I use a Dvorak keyboard layout (built into the Kinesis keyboards).
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Steve
'08 Boxster RS60 Spyder #0099/1960
- never named a car before, but this is Charlotte.
'88 targa

SOLD 2004 - gone but not forgotten