Slate published an interesting article on the increasing dominance of the wide screen format as measured by DVD sales. This has been confirmed by the fact that Blockbuster has publicly stated that it prefers to have wide screen (aka letterbox) format DVDs on its shelves for rental and that most of the top selling DVDs at Amazon.com that are movies are either exclusively sold in wide screen or are significantly more popular in wide screen than in full screen.
A good example of the situation is the recent release of Miracle from Walt Disney Pictures. I think this film has some of the best sports cinematography ever recorded. There has never been a non-documentary film about ice hockey where the scenes of game play has been this realistic. In my opinion, purchasing this film in the full screen format would be a real mistake, even if you don't have a sophisticated home theater.
If this film had come out even three years ago, it would have been difficult to find in wide screen format, on VHS or DVD. Now, it's hard to find on VHS in the first place, and the DVD in full screen format is probably only going to be promoted if the wide screen DVDs are sold out.