After reviewing this thread I thought I'd chime in with a bunch of ideas
I use a 6 mil suit here all winter - water is currently between 2 and 3C. My daughter and other dive buddy both use 5 mils - as did I all last winter.
The trick seems to be the hands. If you order a suit from Elios have them make you 3 finger mitts and boots - they are inexpensive and absolutely excellent.
When I was diving in BC my main problem - diving all day in a 5 mil suit - was the air wicking away warmth when I was out of the water or doing a surface interval in wind. Tyler recommended smoothskin for that so I went with a smoothskin top on my 6 mil. The difference is quite amazing. I would not recommend it as a first suit though because it is fragile but it is very nice. Even with ridiculously strong winds ripping across my back i feel no chill in that suit.
Doc's proplugs (the ones for diving - with little holes in them) will help keep your ears happy. Also - A windbreaker and wind pants to wear over your wetsuit on the boat - and a warm hat - wool or whatever. I use an Omer weight vest with 4lbs in it - it's purpose is only to help hold my upper body down for photography/hunting.
Good gloves/mitts are key over there. I think Henderson Gold core 6.5 mils or insta-dry 5 mils are probably perfect. I used Henderson 5 mil superstretch gloves when I was there and they were just barely adequate. My feet tend to stay warm even with crap socks - but the Omers are definitely very nice. If JimDoe is coming you probably won't need to bring a gun
