Originally Posted by cyccommute

My turn to disagree with nearly everything you've said.

Weight: Mountain bikes...even the lightest ones...are overbuilt. You can start with a lightweight one and add a rack, bags, lights and fenders (only when you need them) and still keep the weight of the bike down to a reasonable level. You don't need to carry as much stuff as many people think you have to. Leave some of the stuff at work and carry only what you need to dress for work.

Lighter wheels: There is no correlation between a lightweight wheelset and durability...at least in mountain bikes. I run Mavic XC717 rims with DT Alpine III spokes and XTR hubs. These are my off-road wheels and I jump them. They are extremely lightweight and durable and, since they are capable of handling off-road conditions, they'll handle anything a street has to offer.

Tires: It depends on what you want to do. Slicks and snow? Not a great combination. Slicks and ice? A really bad combination. Having knobbies opens up the world to make commuting less of a chore and more of a joy.

Disc brakes: I wouldn't call their performance 'superior'. Marginally better in rain and snow but not superior. (Yes, I have disc equipped bikes.) In rain and snow, you are limited not by the braking power but by the grip on the ground. It doesn't improve over dry pavement so having brakes that stop the wheel 'better' doesn't have much effect when stopping the wheel probably isn't a good idea. I've ridden snow, ice and rain with both types of brakes and never found that rim brakes were all that bad. You just have to adjust to the conditions but you have to adjust to the conditions even with discs.