I don't think it has been released yet (and when it is it is likely to be expensive ;-), but this keyboard looks like being a popular choice for gamers, and it also opens up whole new possibilities for application designers in terms of human-computer interaction:

Optimus Keyboard

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Updated 2021 : note that the above post is out-of-date, given this post was originally published in 2006, but is left here for archival purposes.