Some of you probably already read Kris Rusch's blog on the writing business. But I'd urge anyone - whether or not you're self-publishing or intend to - to read this particular post. It pinpoints very accurately, I think, the two different models (that to an extent are warring at the moment) facing any writer now who wants to publish. And for any writer still stuck in the traditional model mind-set (the 'scarcity' model, as Kris puts it), I'd say it's essential to get hold of the massive change in how readers find books that's taking place, and the fact we're never going back to the old way of doing things.
http://kriswrites.com/2012/03/14/the-business-rusch-scarcity-and-abundance/<Added>It occurs to me that the 'scarcity' model might explain the curious fact that a lot of writers don't seem to actually write very much. Is their output being shaped by a model that doesn't require them to produce more than a book every couple of years? In other words, for many writers it could be that their ability to accept the new model is hampered by the fact it will mean having to also accept they're going to need to produce more.