Help Choosing First Bike!?

So I've been talking to some buddies of mine and the old man from the cycle shop down the street and keep getting pointed in all directions. I'm a newbie trying to start cycling for commuting during the week and long fun rides on the weekends with a group of about 50 people. I've been looking at 3 bikes specifically and aside from small features they all seem very similar to me. First up is the Cannondale Cadd 12 disc 105, then the Trek Emonda ALR 5, and lastly the Giant Defy Disc 1. I've heard the disc brakes are a good addition to have especially if you live in rainy areas, which I do. Other than that the major difference seem mostly cosmetic to me but I would like to get a bike that has good quality, and is going to last me for a while. Any info on what makes each bike different or better than the others would be much appreciated!