I've found that the ONLY way to keep your feet warm in very cold water is to have a pair of insulated boot foot waders. Stocking foot waders, regardless of the number and variety of socks worn just won't cut it. With an insulated boot foot and a single pair of heavy wool socks (don't forget the necessary wiggle room for the toes), my feet are comfortable through a full day of winter steelheading. I've pretty well given up on neoprenes except when float tubing*; I find that a couple of layers of polyester and/or fleece keeps me warmer in a pair of breathables than I ever was in neo's. A good place to find things to wear under your waders is your local ski shop or somplace like Outdoor and More (good prices as well) on Westlake, which carries a large selection of backpacking, climbing and related active outdoor stuff. I've found found Lycra/fleece stretch tights to be particularly comfortable under waders. An important thing to remember is to avoid cotton in any situation where you want to stay warm. Cotton will absorb any moisture and will hold it directly against your skin leaving you feeling clammy and cold. The newest polyesters are as comfortable as cotton and will wick moisture away from your body to your outer layers of clothing without absorbing it. Polyester briefs and T-shirts are available from Cabela's and many other places. Wool is probably the best material for socks because of the strength and resisliency of its fibers which, unlike fleece, allow it to retain a little of its loft even after being underfoot all day. I do product reviews for FF&TJ so I've been fortunate to be able to try out quite a few different varieties of breathable waders. They've covered a pretty good range, from Fly-Tech and Cabela's Dry Plus II to Hodgman, Cabela's Goretex, Dan Bailey's and a few others. To me, the most intertesting fact seems to be that I, personally, can detect very little, if any, difference in the breathability of any of them! That being the case, I think the most important factor in selecting a pair is durability. I thought I'd found a real winner in the Cabela's DryPlus II's, cheap and durable, until they began to leak in the crotch after an admittedly hard season (I still think they represent good value for the money). So far, the Cabela's Goretex and the Dan Bailey's seem to be holding up best. I'm hoping to try out a pair of Simms this winter and Chota is sending me a pair of breathables with a lace-up boot foot as soon as they get their first production models out this spring.
*The reason I still use neoprenes while float tubing is that I've found that, since my butt and the small of my back are placed firmly against an impermeable surface while tubing, breathable waders will not breathe at those locations, resulting in condensation and dampness; not a big problem really, but annoying. The same thing happens wearing breathables while rowing a raft or drift boat.
