Will you be doing any other type of riding? When I think of commuting I tend to think of comfort and utility so I probably could not offer much regarding particular bikes outside of my experience. However if we knew your preferences some might be able to steer you in a better direction.

For example I value comfort and utility most when riding with speed further down on my list. In my case I ride a Surly Long Haul Trucker. However if you value speed and keeping up with friends during group rides my Surly would probably be the wrong choice.