Originally Posted by Barabaika
A mountain bike won't serve well as a commuter.
A commuter bike must be equipped for the bad weather: fenders, a chain guard, lights, etc.
It's much easier to put a good chain guard on a bike with the internal hub like Shimano Nexus, and it is 8-speed now with the wide range of gears.
I would have to disagree. I have records for the past 20 years (didn't keep records before that but been riding for another 10) to show that mountain bikes make excellent commuter bikes. 69% of my commuting has been on mountain bikes.
As for equiping them with fenders and lights:
Without the mountain bike I never would have been able to commute during our particularly brutal winter this year
By the way, those are knobbies on the mountain bike. I don't put slicks on my mountain bikes since I like to take off into the woods occassionally on the way home.