Buy whatever you like.

I just built a Disc Trucker for commuting. I want to start touring, so that is the end goal, but it's first purpose is getting me to work year round. My other bikes are race bikes and the Trucker feels marginally slower. I'm talking it takes me only a couple minutes longer to do anything. Even on 2" tires and a wheel set built for someone twice my weight (135) I have no problem riding 22+mph on the flats, with a load. The bike weight only becomes noticeable while climbing, unloaded sprinting out of the saddle (probably looks as ridiculous as it sounds) and while starting uphill from a light. Even then, it's not that big of a deal.