I just got a Das Keyboard. ("The keyboard" in German.)
You can find lots of reviews, so I'll just say: you know how sometimes you get something so good that you just want to use it? This is like that.
This is noisy due to the wonderful mechanical switches (not rubber domes as cheap keyboards have), but not as noisy as my old Matias keyboard (which is also great). There is a new, a bit quieter model of the DAS, but they have to compromise to make that, so it does not have quite the same feel.
This thing just feels so precise and smooth and lovely. And it lets me type exactly as fast as I can get my frontal cortex and fingers to move.