Stumbled onto this thread from a google tangent and having read through the whole thing I signed up here just so I could add a few random, disjointed comments.
One question which came up a lot is why mechanical is better. Sheer comfort has already been covered extensively enough. Accuracy has been hinted at--many cheaper keyboards are rather inconsistent in their response depending on if you hit the keys perfectly centered or not, in addition to the lack of good feedback as to whether a key has registered. Another reason which I haven't seen mentioned yet is the long term effects on your hands; after some thirty odd years of keyboard use I can definitely say that the standard membrane keyboards do strain my wrists after a while. In fact, it was my hunt for a new keyboard which lead me here.
Someone along the way commented that the old IBM PC/AT keyboards lack the positioning nubs for touch-typing. Many older keyboards had F and J keys which were more concave than the rest, which served the same function and which I found much more comfortable. I hated the nubs when they first started appearing and it took a few years to finally get used to having my fingertips stabbed by the various incarnations, from dots in the middle of the key to the bar-shaped ones at the bottom.
Someone else asked for a programmable mechanical keyboard. Just as the Model M is now made and sold by Unicomp, the old Northgate OmniKeys are now made by Creative Vision. They're based on ALPS switches, white if I remember right, and for programmable keys you want the Avant Stellar
Speculation was made regarding the keyboards made by Deck's parent company, TG3. I spoke with Brian Carpenter of TG3 and got a few answers already. The mechanical switches they use are Cherry MX black. There's a rubber membrane which helps spillproof them, and which also lends a slight tactile feel. Sorry, no brown or blue switches.
Right now I'm trying out a Deck 87-key. One of the first things I noticed was that Deck uses PCB-mount keyswitches, and there's absolutely nothing protecting the PCB but the keycaps. Any liquid or metal (such as paperclips) accidentally getting between the keys means an almost certain short circuit. This seems like a serious design flaw, since it would take little to include even slight shielding, either molded in as part of the case or as a rubber sheet. I also can't stand the linear keys for typing, so it's going to be returned.
I have a HHKB Lite kicking around too. Despite being membrane, it seems to be built to better tolerances than most, mostlymitigating the problems of hitting keys off-center. Not the best feel, not quite the worst either.
It almost seems like the ideal setup might be a linear response 10-key specifically for gaming in place of the wasd mapping, since it's mainly the directionals which benefit from that type of keyswitch. Something like one of the X-Keys
could work pretty well for that, negating the need for one full keyboard for gaming and another for typing.