Quickest change?

[Linkex]

This is probably one of those questions with as many answers as people, but I'll ask anyway.

What gear would be fastest to get into? Lets say I do an on call type job, and need to get from "The phone rings" to "On the road" as fast as possible - what is the best/fastest gear to use for the job? Bear in mind it needs to be able to cope with cold and rain, so waterproof is a must.
One piece suit? Separate jacket and trews? What boots?

I've only ever done separate jacket and trews, so advise from anyone who has tried both would be appreciated

 

[Linkex]

Thanks

In terms of sitting in, thats a good point. Ideally I'd like to be able to sit at home dressed in whatever, and then be able to throw my bike gear over the top - assuming its cold enough for me to be wearing something other than shorts at home, its safe to assume that on the road an extra layer would be nice