Touchstream LP

Amazing, but has a very high learning curve and an even higher price ( if you can even find one). I generally use mine when I'm doing work that involves more complicated mouse actions than actual typing or when browsing the web (since I have all the browser actions mapped to gestures).

Pros:
Combined typing and mousing. Being able to seamlessly transition from typing to mousing or gesturing without moving your hands is great.

Highly programmable- literally hundreds of user configurable gestures and settings. Imagine bettertouchtool on steroids x 2.

Cons:
Lack of tactile feedback makes typos a constant issue. Even after owning several touchstream keyboards for many years, I still type much more slowly on these than on a mechanical keyboard and make far more typos.

Availability- the only way you might be able to get ahold of one now is ebay.

Price- absurdly high due to the lack of supply.