Thanks for the input. Yeah, I know the foul weather gear I have isn't cycling/backpacking duty - its Cabelas Guidewear. It works though - I needed a suit that would keep me dry all day if I was out on the lake etc and so far I've been OK with this suit. I agree with considering the gear part of a "cold weather gear" set up, not just wet weather.
As to layers - I have a lot of synthetic clothes that is likely all I'll have, except for socks and underwear. I have a lot of fluorescent yellow "work shirts" that are comfortable both in the heat and as layers for cool weather - both short and long sleeve. Then I have some base layer sets also.
Normally, what I do when it is "cold" (down to below freezing to start off) is I put my bike shorts on first, then 2 base layer pants (1st layer with my socks over top the pant cuffs, that keeps them in place when I go to layer 2) then my convertible backpacking pants on the outside (with the pant legs zipped in, of course). For the top I use a short sleeve shirt mostly, unless it is really cold and I know I wont need that layer then I may stick to long sleeve as a base. Then its another layer or two of long sleeve shirts and a fleece jacket to cap off the "layers" inside. Depending on the temp, I have a thin wind breaker that I wear over top that (cycling, its vented in the rear really well - very open) or I will put on a heavier coat. Of course, that is the beauty of layering - you have lots of options set to go depending on conditions. As for the outside layers - if I need a coat the foul weather coat would suit fine. I use it every once in a while as a regular coat anyway. I am not sure about the pants. They are full blown chest-high coveralls so the layering with them would work out a lot different. However, if getting wet is likely, I'd rather already have the coveralls on than have to stop and work up that layer (take shoes off, etc, etc). I do that on the lake - I just wear the coveralls all day so I don't have to screw with getting them on. Though, in that case I am not exerting the energy I would be on a bike = not heating up inside.