The most comfortable I've owned are ECCO's. I used to have a lot of heal pain from walking around the office and data center but since I've bought the ECCO's I've had no pain and no problems walking however much I want. I have very flat feet so take that as part of YMMV.
My latest shoe purchase was a pair of ECCO's. Bought them at DSW for considerably less than they were selling for on zappos.com at the time ($165 vs $100). Have been very happy with them. However, the most comfortable shoes I have are Clarks. I wouldn't exactly consider them dress shoes, but I get away with them at my workplace that tends to lean towards the casual side of business casual.