To be honest with you, don't let money be the deciding factor, at least with the offers you've presented.

A worthy developer, even at a startup, should be making 70-80k a year easy + equity.

If I were you and really wanted to move, I would get a better offer then move out.

Otherwise, moving to SF at the moment is a hassle and at that income you're looking at living far away from the action anyway.

Granted, there are other things to consider, but consider this just a point of view from the money side.

That said, I find that when people post questions like this, they aren't generally looking for advice. Rather, it sounds like you really want to move to SF and are just looking for encouragement. If that's the case, you'll probably end up moving here anyway so just get it over with ASAP :)