I'm planning on extending my commuting season to year-round. For me, winter conditions are less focused on just temp, and more on the road conditions (packed snow, salt, ice, etc.) I think I've got the clothing part under control thanks to cross country ski experience, but have a few practical concerns for the winter that I'd like to get a head start on:

Bike- I have one steel or one alum MTB to set up as a winter bike. The alum bike has a suspension fork and is configured for single track. The steel bike is older, and is my former commuter with slicks. Any clear choice between the two?

Rims - Disc brakes aren't an option, so I'm wondering if there are any methods for reducing the damage caused by salt/sand.

Tires - I've considered making a (front only) studded tire out of a knobby using sheet metal screws like
this. How necessary are studs? knobbies?

Fenders - I'm a big believer in fenders. For a MTB setup in winter, do normal fenders or high-clearance "clip-ons" work better?

Pedals - As much as I love clipless, I'm thinking that cages and an insulated hiking shoe might make more sense. Any favorite shoe/pedal combos for winter?

Electronics - How do people protect electronics such as laptop computers and palm pilot/cell phones in bitter cold?

I've got time on my side, so any good direction get me on the right track. My ride is approx 11 miles each way, one or two hills, and medium traffic roads with rough but paved shoulders in the upper midwest.

Thanks in advance.