I use a HHKB Pro 2 and I believe it's as close to keyboard perfection as humanly possible. It's evident from the pictures that it partially inspired this CODE keyboard.
I'll add my voice to "the HHKB2 is the greatest keyboard imaginable."
Also, re: arrow and paging keys, I manage to avoid them as much as possible, but reaching for 'Fn' with the pinky and hitting the appropriate key with my index or middle finger became second nature rather quickly.
Also, rarely noted — and the thing that every single keyboard gets wrong, including Atwood's here — is that the HHKB has the Escape key in line with the number row, so that it can be reached easily without taking your fingers off the home row.