There are multiple factors to consider, and there is no single right answer here.
1) How much are you carrying? If you have 60+lb of equipment/food/clothes in your bags/racks, you want to go wider. If just yourself and your bike, narrower is fine.
2) How bumpy are the roads? Naturally, wider is good for rougher roads while narrower can be faster on smooth roads.
3) What's more important to you: comfort or speed? (This has already been discussed)
I have had two vastly different commutes, so I had two vastly different ways of doing it. When I rode to work every other day, 21 miles and ~1200' of climbing each way, and drove my clothes and stuff on the alternate days, I used my road bike with skinny tires and wore my lycra kit. When my commute became a daily 6 miles pancake flat, I put 1.4" slicks on a mountain bike and carried my stuff in a child trailer while wearing my work clothes.
__________________
It's like riding a bicycle