My planned set-up was to have Disk & Cantis in the front and just Cantis in the rear.
My thinking was that I would need the disk (just in the front) during the rainy seasons (here spring/summer) for commuting in the city and on the muddy trails. But most of the dry times I would be using only the cantis (front and back). I have no intention of using both cantis & disk at the same time. And I'm not too concerned about the extra weight.
Does my idea seem loony? Are the cantis enough, and therefor I shouldn't worry about getting disks for the rain? The reason for my paranoia is the fact that I've lived in SUNNY Southern California most of my life and just recently moved to a place which actually gets plenty of rainfall. So, I'm just trying to think ahead and prepare myself, but then again maybe my planning is overkill.
By the way, once I get my Cross-Check here I'll likely be only the second guy out of a local population of 750,000 with a cyclocross bike. It's funny, bike shop owners change the subject when you bring up CX or 29er's. It's all new stuff to the people of this region.