I'm in Montréal, not Anchorage, so I can't vouch for your Winter conditions, but I feel they are relatively similar. So here is what I need and I think what you might need too:
- Fenders: sounds silly to start with that, but fenders not only keep the cyclist cleen, but they also protect the bicycle and its drivetrain. You need a long mudflap on the front wheel, and preferably wide fenders with lots of clearance. I don't have problem on one bike that has 5-6 mm clearance between wheel and fender, but the one that has 12 mm behaves definitely better. And you tend to get overflow with SKS 700x45 fenders around 700x37 tires; wider fenders, such as 60 mm ones would be better. Which means you need a bike with fork and stays designed with enough clearance for that and decent tires! In installing fenders, you should start with a narrow gap in the rear and make it wider, so you won't pinch any snow.
- Tires: Fat tires are good for hard packed snow. Even if you ride before the streets are plowed, the snow won't be hard enough to float on it, so the 3" wide tires of the Pugsley will still cut through the snow. I prefer tires with a decent tread (tractor tread for instance), and maybe studded tires if there is rugged ice, frozen iceruts or any other kind of similarly difficult conditions. In practical terms, I use either Vittoria Lizzard 700x37, Specialized Cyclocross 700x37 and one other whose name escapes me (bought at different times) during winter, and may install Nokian Hakkapeliittas 700x37 if the weather warrants it. I never felt the need for more than the Hakkapeliittas: usually if these tires can't carry me safely, the snow is too deep and I should use snowshoes instead.
– Gears: low gears for difficult conditions. I never had any problems with a derailleur system and never had any problems with a freewheel, but freehubs don't like temperatures below -15 or -20 C. I must stay that fenders have done a great job in keeping the drivetrain OK. On the other hand, I re-grease my LX hubs every 2-3 years and sometimes wonder why I do this, because the grease looks like new, even though I rode 5000-7000 km per year, including 1000-1500 km in Winter. As for internal gearing, I'm a bit sceptical: it's probably very good in humid and not so cold conditions (ex.: 0 to -5 C), but I'm weary of its behavious at -20 C and I'm also weary of the shifter at -20 C.
– Lights: For headlight, I use a dynohub with a Lumotec or Schmidt headlight. It never fails in the cold. For taillight, I use battery LEDs (always more than 1 – currently Cateye TL-LD1000 and Planet Bike Superflash) but have to watch their brightness often. At -20 C, I find that Energizer batteries last longer than others I have tried; I haven't used rechargeables at low temperatures yet.
– Brakes: I use rim brakes with Kool Stop Salmon pads. Braking is a problem if I haven't used the brakes for 20-30 minutes (ex.: riding out of town), but in the city, they work decently well: they need 1-2 wheel turns before grabbing well, but since I can't brake too hards because of ice anyways, it's not a real issue. I know that disc brakes work fine in the rain and especially in muddy conditions, but I wonder if discs freeze and stop working in adverse winter conditions. It's worth exploring anyways! Or get both disc and v-brake brazeons!