Well, for under $50 anyway...
Kensington Comfort Type Multimedia Keyboard
Recently to match the new PC upgrade we did I picked up a new keyboard after seeing one at CompUSA. Its made by Kensington, a company that has been around for what seems like forever (at least in IT-world terms, i.e. 15-20 years) and at first glance seems the same as any other on the market with its multimedia keys and fairly generic layout. However, after laying your fingers on its keys you notice something different - the keys are slanted!
Those kooky folks at Kensington must have spent way too much time looking over people's shoulders while typing. It seems they noticed that when most people type their hands tend to angle away from each other with the backs of the hands pointing over the typists shoulders and fingers pointing inwards. Go put your hands on a keyboard, let them rest and see what way they lie. So they took this knowledge and designed a keyboard that slants in the direction your fingers are pointing.
The first time I saw the keyboard it seemed a bit strange but typing on it for a few seconds, even not plugged into anything, I could immediately tell that it fit my natural typing position better than the generic un-slanted keyboard, and so the next time I was at the store I got one.
The only negative side I can see is that the back-slash / pipe key, which is usually above the enter key, is positioned beneath the enter key. This has the awkward effect of both having to re-train yourself to a new location for a key often used by geeks (i.e. me), and also making the right shift key narrower. I'll live, but I wish they left it where it should be.
Lastly it must be mentioned that this is a PS/2 keyboard, i.e. that little round connector which has been standard on PCs for ten years or so. Personally I think that it should be USB as standard, USB has been on PCs since the late '90s and there's no excuse these days for not shipping devices that are USB compatible, at the very least bundling an adapter. Heck, our new computer has about ten USB connectors, never mind using a USB hub.
Kensington sell multiple varieties of the keyboard, with this one ranking at the $20 mark with two others available without the multimedia keys - one beige PS/2-only keyboard for $15 and a black PS/2-USB one for $20.
So next time you are looking for a keyboard I suggest seeking one out and giving it a spin, you might just like it.