He couldn't or wouldn't say it before – it sounds too close to implying that he regrets the choice he made, and I don't think Dean could ever regret choosing Sam's life over his own. He just isn't made that way. But now he's managed to admit that he doesn't want to die, doesn't want to go to hell, and that's a huge step forward.

Dean breaks me into small pieces every time I watch that part of the episode! Ack! And I love that Bobby is their father figure, and they're the sons he never had!

As far as Bela goes, I agree she does tend to feel shoe horned in, but I never mind it when she manages to steal things from the boys because that's what she is. A professional thief. Sam and Dean are good thieves, but Bela's a 'great thief'. I think it would annoy me more if she couldn't do it so well because then it would be a question of "How the hell did this chick manage to make it this far in this business?"

I have no idea where Sam's Bela fantasy came from.
Yeah, that was a big "what the hell?" moment for me to. But Sam was so wonderfully dorky about the whole thing. =)