The space bar as currently implemented is a waste of keyboard real estate.

Cut it in half, and give the left thumb something to do.

I actually like it as big as it. When typing with correct posture, you can press it with either thumb as needed.

True, but remember that thumbs these days are more articulate than ever before, thanks to a generation of kids texting with them for hours on end. You could put four keys there, used for navigation, macros, you name it, and not slow anybody down. Also, the locations of critical keys like ctrl, alt, (command and option for the mac lovers) is painful on the pinkies, which haven't caught up to the other eight fingers yet.

I never thought about it before, but it's true... That space could be used much better.

It is a waste of space, but it's useful as is. I wouldn't have it any other way.

My dad had (has?) a keyboard with the spacebar cut in half. The left half was a backspace key, the right half was the space bar.

Try as I might (and I was visiting for 2 months, I had the time to try) I never grew used to it, and I've used a japanese keyboard!

I don't think there's anything feasible to put in that space. And keyboards with shunken spacebars are so annoying.

There's a reason why I use http://www.microsoft.com/hardware/mouseandkeyboard/productdetails.aspx?pid=043 <-- this keyboard and love it so much.