The one that "feels" best in my hands. Keyboards (and mice) are extensions of our own hands and fingers. What feels great at the end of my finger tips may feel totally awkward and unusable to you. Some like a wavy boards, some flat. Some (like me) like a curved keyboard, some straight. Some don't care about number keys, some want them. Some prefer number-pads on the left. Some want long throw keys, some short. Some solid "mechanical" "clicks", some soft. You need to visit your local computer store and play touchy-feeling with the keyboards yourself and find the one that feels right in your hands.
