Need a quiet keyboard

[zillac]

I have a mechanical keyboard right now at hand, and me typing on this keyboard can be heard by the whole house late at night. Walls are too thing at where I live : |

I'm looking for a keyboard that is of quiet, good quality, and keys should be relatively firm. Classic layout without media/extra buttons is preferred, wire/less is irrelevant. Price is not a major concern since I will be using it A LOT.

Thanks in advance.


p.s. I will jump on a HHKB if I see it on fleabay