I'm a fan of flexibility. So I have leg and arm warmers, a jacket with removable sleeves, neoprene shoes "toasties" (easy to stash in a jersey pocket), as well as a long sleeve jersey with a built-in hood. Lots of adjustability, eh?
It's all very handy for those long recreational and group rides that start in the early AM, too. Also, I like to compare against what I wore "yesterday".