Wool is by far the best base layer material. Lots of good options – smart wool, ibex, heley hanson, patagonia, etc. Midweight is good for ice fishing — breathable, you dont get too sweaty getting out and getting set up, and you stay warmer sitting too. I usually wear my baselayer, some sort of hoody, and maybe a fleece jacket depending on the cold and if Im going to be out and about or hunkered down on a spot.
For socks, wool all the way. I think people put too much on their feet and they get sweaty/cold. I like the basic midweight ‘light hiking’ style socks. I’m a big fan of Wigwam or REI, but smartwool etc. The cold sneaks up from the bottom, so a nice felt insole will go a long way in keeping your feet warm. Plus anything you can do to get your feet off the ice if youre going to be out there for a while — small mat or whatever.
Wool isn’t cheap, but its far superior to even the best synthetics. Nice thing is that wool doesnt get smelly like the synthetics too — so you can get one nice set and wear it all weekend… Best place I have found for prices/service is Midwest Mountaineering when they’re having their monthly sales. Go for a ‘pint night’ and get a pint glass (with beer) and get a good deal.