I'm also intrigued by this idea of Charles Widmore as the deposed leader of the Hostiles/Others...but I don't buy it.

There are too many contradictions there. First off, even though it isn't completely canonical, The Lost Experience leads us to believe that the Widmore Corporation was working with the Hanso Foundation...not something that a former leader of The (then-)Hostiles would do given their antagonism toward the DHARMA Initiative. Then, there's also the question of Penny...if he was raising her in her youth (assuming, of course, that it wasn't all boarding schools and nannies) and he was the Big Kahuna on the Island, wouldn't she have been raised there and not had to "do some research" to learn about it?

I'm much more inclined to think that Widmore and Hanso (who, lest we forget was an arms dealer before he was a would-be world-saving philanthropist and patron of questionable science) were using the DHARMA Initiative as a way to harness the Island for their own purposes and that they (or at least Widmore) saw it as "theirs" because of that.

I could, of course, be wrong...