If you can use a corner, an L-desk is probably your best solution. Unless, of course, you have a super-treated “pro-level” room and you want your desk to be right in the middle of it (as it should be.)
Something like this:
http://www.staples.com/Z-Line-Designs-Delano-Glass-Top-L-Desk/product_750723
Or you can put your keyboard on a laptop cart and tuck it underneath the deck when you’re not using it.
http://www.staples.com/The-Sharper-Image-Adjustable-Height-Foldable-Laptop-Cart-Black/product_320956