How long is your commute? Most people don't need anything super special for commuting, any bike will do.

Road tires
Rigid fork (although not all that necessary and a susp.fork may help with potholes)
Fenders (not only for rain, but when ride over fresh dog poo... you get the picture)
Rear rack (so you can carry stuff in a rackbag or pannier instead of a sweaty backpack)
Lights