I have feet that are very wide and very flat. I have used Cannondale shoes for a number of years, and have found them comfotable and accomodating. They even accept my custom orthotics. One thing I have found about the Cannondales though is the sizing seems to tend toward the small side. I normally wear an 11 or 12 shoe, but I had to go to a 13 in the Cannondale just for the length.
Dan