Honestly, I'm not a fan of disc brakes. I got them 10 years ago on my mountain bike, and I found them to be a complete PITA. Difficult to adjust, difficult and expensive to install a rear rack on a disc-brake equipped bike, and once installed, the kluge made it a colossal PITA to change a tire. I also don't like that the brake pads are harder to change and there are all manner of incompatible designs.

I can see their value for:

1. Tandems. Oh yea.
2. Road or mountain bikes used in the rain/mud often.

Neither of which applies to me. So if they become the norm, I'll be dragged in kicking and screaming.