If you want the feel and responsiveness of the mechanical keyboards but the quietness of the laptop keyboards I believe DAS keyboards offers something like that, here http://www.daskeyboard.com/ look for the silent model, it might be worth it if you're going to type in a crowded environment where others might be bothered by the clicky noise.
It might be a little louder than my old keyboard but it was not nearly as loud as I thought it was going to be. Here in my computer room at home I'm sure someone else in the room could hear the keys as I type but they're not what I'd call super loud.
Razer has since put out another version of this keyboard called the Razer Blackwidow Ultimate Stealth Edition (there is also a non-Ultimate Stealth Edition). The Stealth Edition has Cherry Brown switches which are much quieter. If you want this keyboard without the noise, you can get the Stealth version directly from the Razer online store. Hopefully Amazon will stock the Stealth version soon.