When it comes to keyboards, there are two types: mechanical planks and everything else. I can say that with complete confidence after having gone through and used or otherwise tested a number of keyboards over the years -- for the most part, squishy membrane keyboards just don't compete (though the Mad Catz S.T.R.I.K.E. 3 is a valiant effort). In case you're interested, my daily driver these days is a Das Keyboard 4 Professional, which you can pick up today in factory reconditioned form for $120.
We've been fans of Metadot's Das Keyboard models ever since the first one debuted back in 2005. These mechanical keyboards started off as a sort of throwback to the clicky IBM Model M planks from a million years ago, though one unique feature of the Das Keyboard is that you could get a version with unlabeled keys for added geek points. There have been a few different iterations through the years, and now there's a new model -- the Das Keyboard 4, which Metadot says is the most significant update to the series since the original.