Id rate a light-touring bike as the ultimate commuter. Deep drop calipers, up to 32mm tyres +fenders, rack, lights.
With horizontal dropouts you have the option of hub/fixed as well as derailleur gears.
I prefer touring drops (3TTT Morphe), but there's no reason you cant fit flats on the bike.
The ideal commuter is one you customise for your own conditions. You just have to be aware of the options, which extend way beyong anything you will see in the average big-brand bike shop.