I personally prefer Cherry MX Browns. They have a tactile bump where the switch activates, but no tactile click like the blues, making the browns much quieter.
I have used one of those Logitech keyboards. I like using scissor switches over membranes, but I didn't particulary care for it. If quiet is your biggest priority, then a mechanical keyboard isn't for you.
I'm looking at mechanical keyboards too. whats a decent keyboard with the cherry MX browns thats not too expensive? is it possible to get a backlit mechanical keyboard?