Blocking wind and insulation seem to be the big issues. I went with windblocking toe covers and some wool socks. It's not as cold as your area, it's New England, not MN. But it seems to work ok for me down to 25F.
But if I lived where single digit, teen temps was a normal winter day, I'd invest in a pair of NorthWave winter boots and wear wool socks with those. Given that winter season is short compared to Spring+Summer+Fall and probably not riding as much, I think the winter boots should last 5 years +.
That's what I would do, not toe covers, I'd spend some money on a warm pair of winter boots made to fight cold winds and snow. NorthWave are well known for the winter sport footwear, so I'd go with them personally.
Last edited by zymphad; 11-16-14 at 02:28 PM.