Bike Jacket

skull cap, shoe covers, warm (wool?) socks, polypro glove liners and all the other standard cold-weather gear. 

Invest in GREAT base layers and you can get away with less than stellar outer gear. IMO.

I should trust a guy from Idaho on cold weather gear, no?

Are there a certain number of layers when you don't worry about wearing chamois bike pants anymore?  I did buy some "knicker" bike pants, which felt great this morning in about 48* weather.

I have a whole bunch of performance-type mock turtlenecks and some synthetic long undies.  I use them for fly fishing Would you wear them for rides?  I am worried about blisters in some sensitive areas.  Broken bones, back spasms, road rash; These things I can handle!  Blisters?  Not so much!

I ride if it is 20 or warmer. I wear different clothes depending on real feel temp.

I have 2 or more different items for different temps for most things. Tights you can get that you put over bike shorts. If you get bike tights they tend to keep you from slipping on the saddle. I have run tights that if I use I slip in. 

Bike Gore Wear is the best as it is truly wind proof and keeping the wind off me is the key to being warm. Performance carries the brand at good prices.

Pearl Izumi stuff with Amphib is good for the coldest weather..I have their booties, gloves and tights.

I have 6 or 7 winter bike jackets, 4 pairs of gloves, 4 hats, and 3 pairs of tights and I wear different combinations depending on temp, sun/shade, and wind.

My go to jacket is the Bike Gore that I wear often over a regular winter jacket.

Let me be the first to focus on the second part of your posting:  Yes.

A tri-bag, or dedicated bag of some sort is very helpful.  I have an old backpack that I use (it was designed for adventure racing, so it has a bungee on the outside for helmets).  I keep a spare set of goggles, race belt, towel, some cliff blocks and a bottle of water in it at all times.  If I was more concerned about forgetting things, I would put a back up pair of running and biking shoes in it.  It hangs in the gear zone next to the wetsuit rack, so I don't think I need to keep the wetsuit in/on it. But as it is, the bike shoes and helmet live on the rack with the bike on the wall, so when I grab the bike I grab the shoes and helmet.  And part of my race day routine is to wear the tri top and shorts and running shoes for the drive to the race. A spare floor pump and full size towel live in the gearmobile.  The most likely thing I would forget is the least critical - HRM/Garmin. But I keep a spare HRM (basic timex) in the gym bag that also lives in the gearmobile, so I am still covered.