I know a lot of fat people that love Flow bindings for the comfort and ease of entry. These are consistently the most comfortable bindings for me. These are what I own, but in the 2010 version(I'm 5'9 185lbs though
Flow NXT-FSE Mens Snowboard Bindings 2011
They are fairly stiff so it will be a good match to the Heritage.
The Double Agents are sick as well. Very adjustable bindings.
Ride Double Agent Snowboard Bindings 2011
A good alternative to the Double Agents are the SPI's.
Some other good bindings for you:
K2 Auto Ever - stiff and responsive. Set up takes time to dial in, but once you do, it's very easy to strap in as the toe strap tightens as you crank the ankle strap down.
Rome Targa - The 2011 version comes with their Yes I Cant system which gives you three cant bed options with varying degrees of canting that you can mix and match. Very comfortable once you find the right setting especially if you have a wider stance
The SPI, Double Agent, and Targas all have inserts that allow you to customize the flex of the ankle strap.