I looked at the Giant OCR Tour, the Cannondale T800, Fuji's Touring bike and Trek's 520. I rode all but the OCR Tour, but the stress a disk brake buts on spokes turned me off. I am 195 and have concerns about breaking spokes with my weight and the 30-35.bs of gear I will carry front and back. No need to make the problem worse.
As for steel vs aluminum, go with what you like. "Steel is real" is so overdone and annoying. For big guys a good aluminum frame makes a good deal of sense, much less flexy then steel. I bought a T800 and it felt much better to me than the Trek 520. Plus, the out of the box gearing for 2005 rocks! Component spec for a bike that will see a lot of hard times is nice too.