I've yet to try it fishing, but I work as a forestry consultant in west central Alberta. What I wear daily all winter down to -25C is polypropelene liner gloves ( the blue helly hansen ones $10) under wool fingerless flip top mitts with the thinsulate insulation ( $10 for these too).

I work outside all day with two sets of these that I change when too wet, however the polypro stays warm even soaked and the flip mitts are great to warm the hands when needed.

Like has been said, it's hard to find a perfect solution, but this is probably the best one I have came up with except a bunch of twigs and a zippo. My hands stay warm most of the time but there are days that they freeze, and a quick fire is all I need to get going with work again.

-Hillard