No keyboard stands! The use of sloped keyboards or keyboard stands (the little legs on the bottom of keyboards) requires that we type with our wrists bent up, rather than in a resting/neutral state (wrist extension). This posture, aside from increasing pressure through the carpal tunnel, demands constant activation of the extensor muscles of the forearm which can result in pain, tendinitis and other problems.
You will notice that low profile (flat) keyboards are increasingly available on the market. These are a better option than the traditional sloping keyboards.
Here are links to four low profile keyboards – two for PC, and two for Mac. Note that the title “Keyboard for Notebooks” for one of them is a bit misleading, as the product is a full size keyboard perfect for home or office desktop use.