I hate MS, and I basically want them to die, BUT: Get a Microsoft Natural Keyboard!
These are the "broken" or "angled" keyboards where the left and the right parts of the keyboards are angled towards each other, with some space in between. This makes the hands not having to do this awkward angle vs. the underarms.
I've been through several iterations of them, some of them are not that fantastic. The current keyboard is a "Microsoft (r) Natural (r) Ergonomic Keyboard 4000 v1.0" (!!), and it is very, very good.
Use the front-lifting device of it so that your hands get in the 100% natural resting position (On my keyboard, when I just hold my hands out in front of me and lay them down on the keyboard, I don't need to adjust any joints!).
Get a mouse that does not skid one single pixel, ever (laser mouses are good - ball mouses are evil. Remember to clean the camera and diodes once in a while). "Invest" in a cordless mouse (cordless keyboard is no use if you're at your desk, but cordless mouse makes much sense, as the cord doesn't get in the way, and doesn't move the mouse because of its springiness). Get a proper mousing surface with a gelly wrist rest (I've got an old "3M Precise Mousing Surface", but I haven't seen them around lately. It doesn't work fantastic with my laser mouse either, actually: I have a normal mouse mat on top of it! But it has this silicone pad for the wrist, and is made of rigid plastic, not some flimsy BS).
Seriously, if you have hand problems, like you feel an itch, or unpleasant feeling, on the top of your hands (the "lifter tendons") after a while of typing, or wrist problems - I'd totally invest the couple of dollars in the gear suggested here! It helped me 100%, and it might help you. (I can't use a normal keyboard for more than half an hour before I want to throw it in the wall and get an ice bucket for my hands). (Some say this also helps for the rest of their arms and shoulders - but I haven't had any problems here, so I don't know..)