My girlfriend has browns, and since they have a step in them I find them to be louder. I prefer the reds because as you press it down it has the same force the whole way through. They key itself is audible, but it doesn't have a loud "click" like some of the other colors. I couldn't tell which is the absolute quietest, though it's definitely quieter than the blues or browns. Overall, whatever switch you like comes down to preference. I think they're all noisier than a membrane.
Depending on your headset and how much gain the mic has, it might pick up your keyboard noise. I can say that I've never heard my keyboard over my mic at home. If it's picking up I suppose you could always lower the mic volume a bit.
Hope that helps!