1) Nokian studded tires--have them, I think they are essential. What do you think?
I *love* my Nokian tires. Kept me from crashing out last winter, and that's just a good thing. They don't seem to slow me down more than normal MTB tires do, either. Granted, I change wheels when the weather is nice (read: non-snow & ice) but your mileage may vary...
2) Disc brakes: Front & rear or just on the rear? What do you think. Any brand recommendations?
I just changed my racing bike's (Trek 5200) rear break pads (sic) after about 700 km of riding. I wasn't all that happy about it, but the pads don't seem to have much on them (Ultegra) and I ride in all weather, (it's been wet lately) so that's a thing to be considered as well.
Although I recently got a new used bike (SBI Fully) w/o disks, I think that they'd be a good idea. Expensive, since you'd really want TWO pair, one for knobbies, one for street use, but there you are...
3) Hard nose vs front suspension: my inclination is to a hard nose, how about you?
Again, as my life insurance is self carried, I find that suspension is awfully helpful when hopping curbs at opprotune times (a.k.a. truck of death is bearing down on you), also, it's nice and cushy. Last year I rode a front-suspension Bontrager, so it's a test with the fully this year...
4) Cyclo cross vs MTB frame? Because of fitting problems, I will probably go with a MTB, but which would you choose and why?
MTB. I've got way too many bikes as it is without getting a CycloCross (wait...I've got one in parts back in the USA!) on top of it.
5) How about internal hub gears? Are any made for 26" wheels? Can they be used with Disc Brakes? Are they really better for slush & mud, or is that just traditional wisdom?
I think that the Rohloff (
http://www.rohloff.de/english/index.htm) is just a great idea, and would love to build up a commuter on it. Just another thing to do.
Good luck this winter!
Tom