I remember typing on the HP XT keyboards from 1992 or so. They were soft touch with no click, you just go all the way down smoothly if you push hard. This would allow one to type silently without causing the keyboard noise.
Where can I find such type of keyboards?
EDIT: I bought the Dell KB216 and presently am happy with it. Let us see how it ages.
Presently I have this bottom of the barrel Logitech K200 membrane keyboard where the keys do not go down smoothly and hence fail to register.
I was thinking of lubricating the keyboard but found out that it only works for mechanical ones.
I have read through this review and decided to buy the Dell KB216 for now. The Logitech one is wireless and for my desktop I want wired one. Wireless ones tend to go to sleep and do not respond instantly after a long period of lack of use.