I'm a big fan of one bike to get started and another bike as a reward after some pounds dropped, especially for a new biker when they'll be developing a better idea of biking likes/goals/dislikes/etc. I started out at 380 on a 2008 Specialized Hardrock, threw some big road tires on it (Schwalbe Big Apples) and had a great first year commuting and building up to a several centuries on it last year. Hardrock is cheap, durable, and has a nice comfortable upright riding position. Down to 245 now, treated myself to a new bike a few months ago.
If you search around the Clyde forum, you'll see a whole pile of threads of similar folks with a ridiculous number of recommendations for folks in similar sizes.