I have my commuter, a converted Trek 7000 MTB, and my array of road bikes. While I've done the commute on the road bikes I'm much more comfortable on the commuter. I can ride the road bikes faster of course, in particular up the bridge, but in NYC traffic speed does not get you there any faster.

I have an array of accessories on the commuter, rack, dynamo lights, fenders, whereas all my road bikes are completely bare except for the water bottle.