Hi, Mike

I think cross bikes would make a great commuter,for the money the Surly crosscheck is pretty good. Other mid priced cross bikes ,the Jamis nova ,Fuji cross. Montlake bike I think has some left over Diamondback podiums , these are even set up for disc brakes including hubs. I'am leaning towards a cross bike,but also looking into a touring bike. With a touring bike you can carry a bigger load with more stability.[ panniers, with more heel clearance] . Like you I use a messenger bag ,but sometimes panniers would be handy. I hope this helps.

Pat