As with Don, I use heated seat and grips for the starting to get cold days.
After that is is full on heated gear.
Gloves, jacket liner, socks or boot liners and pants if needed.
The older you get the more you need it. I use the grips probably 9 months out of the year. Arthritis feels better with warmth.
Heated pants liners are about he only item I don't use on cold days (<the 35).
I have a pair of leather coveralls that I got at the NYC show that have the option of insulted liners. They really help and are good down to about 25. I use that number because for one 25 degree day I had the heated liners on and turned them off within 4 miles of the house.
If I had no heated gear and was starting the purchase route I would go in this order:
Gloves
heated grips - see "Heat Demons"
socks (or boot liners)
jacket or vest
pants
Alternator upgrade
Any with any of the heated gear, thermostats make the system work best for you.