I go base layer pants, crash pads, and shell pants - maybe add in a pair of cold weather compression shorts if it's really cold or wet.
I'm actually a pretty big fan of my crash pads as a couple years back at the end of my first year I took a fall onto some ice and broke my tailbone. I was barely even moving, just came off the chairs and someone was down in front of me so I tried to turn and just kinda tipped over. Landed rear first on some ice and it was all over. Took 16 months before it stopped hurting permanently - but having the crash pads last year I went down hard a couple times on my tail and was able to pop right back up. They may be a pain to wear, but it beats the alternative for me.