The best ergonomic computer keyboard is the Microsoft ergonomic 4000. This may just be an opinion but it comes backed by research
and personal use. My pain level has eased while my comfort and speed has improved.
There are wrist pads for comfort and different height adjustments to angle the keyboard to the front or rear.
Where the keys split is a zoom in and out button, this enables better page control. Below the space bar sits two more buttons for forward and back page turning that assist quick movement through a site or document.
There are shortcut buttons that allow you to access the web or email quickly, along with many other useful buttons for speed and ease of use.
I thought this was going to be hard to use at first, but it actually helped to improve my typing. The split and angled keys relieved stress on my wrists, allowing me to move faster. There is a soft, but firm key push resistance that has to be experienced to be understood, it feels like quality, leaving you sure of yourself.
The additional control buttons allow me to move through a document or site faster. There are different height settings to improve comfort and lessen stress. I found one I liked with the keyboard tilted back, this let my wrists sit in a more natural position.
Because the keys are split for the different hands and angled, some of the keys at the split are larger. At first, this created some misspellings, but after and hour of typing I adjusted and it feels normal now.
The biggest benefit I noticed was in the lack of wrist pain at the end of the day. I do a good amount of typing and know there are people that do much more than me, this could help many of the people that suffer with wrist pain as it has helped me. I own three of them.