I'm with Dan on this one: I haven't seen a lot of Democratic enthusiasm for budget balancing this cycle.
Democrats like so say they favor balanced budgets, of course. They've invested the Clinton tax increase with nearly the same level of totemic power as Republicans have given to the Reagan tax cuts: it allows them to claim credit for a largely unrelated economic boom. But this is just something to say when you're bored. I see the candidates promising to spend all the money they claw back from the Bush tax cuts (which will be a couple of hundred billion between their first budget and the expiration of cuts), and more besides. This would seem to bely any serious interest in deficit cuttery. I don't know many progressives who would prefer deficit reduction to, say, national health care.