diver_paula:2) Drysuit undies - unless you are diving somewhere that's not particularly cold and could layer sweats and the like underneath. Paula
Thanks everybody for all of these great comments!
A Few More Questions....
About the UNDIES. Friends of mine have full-body fleece suits made for diving. I'm thinking I can get away wearing the polypropylene and fleece tops/bottoms I use for backpacking? Is this foolishness?
About the LEAKS. If you had a 'catastrophic leak' with a real hole in a shell-type suit, wouldn't you fill up with water, suffer shock from the sudden cold-water immersion, and then have difficulty surfacing? Admittedly unlikely, but do people survive this? This makes me lean toward a neoprene drysuit (regular neoprene, not the snazzy compressed neoprene).
I have been a steadfast wetsuit diver (7ml farmer john/longsleeve top with short legs), but when it drops below 9 degrees C / 48 degrees F, one can only use the "suit-warmer" so many times in a dive and then go home with lots of air left. A new wetsuit will probably do it (this one shows wrinkles so the neoprene might be compressed), but a new wetsuit and a used drysuit aren't so different in price. There seem to be a lot of used suits in my size (short and scrawny).