I really have to wonder what happened to Walt and how he and his father apparently got separated again. Did Walt willfully leave? Did he 'displace' himself back onto the island? He's most likely still alive, because the preview for next week's episode seems to indicate that Ben still has Michael wrapped around his finger, playing his paternal instincts and desperation against him. I'm also afraid that this will be the episode where 'future Ben's' reminder to Sayid about "Remember what happened the last time you thought with your heart and not your gun?" will be made clear.
I also found the fishing conversation very telling, as I think it's pretty clear now that Locke and Ben are squarely in the "dark" camp, even if everyone in Locke's camp is not necessarily so. Bernard labeling those who stayed with Jack the "good guys" seems a lot 'truer' than Ben's perversion of the phrase.