$500 because that's how much I've saved over the past few years by having ONE keyboard I love and not screwing around with aftermarket key caps and different switches and blah blah blah. Sure, I decorated it with a couple of colored mods and put an excellent PBT space bar on it to ward off the shine, but that's it.
The HHKB ships with awesome, thick PBT key caps and while people love to ***** about it being plastic, the fact is the build quality is incredible and it weighs nothing in my bag. I love the layout, love the compactness of it, love the sound and feel. I pop my key caps off a couple times a year and give them a scrub, vaccuum out any dust, and I'm back in business.
I see myself typing on this thing years down the road -- with the one caveat being that if I should decide to start writing on an iPad or something, I guess I'd be wanting the Bluetooth version instead...