The fact that Joe Lieberman and Blanche Lincoln have the highest disapproval numbers of any Senators we've looked at in the last six months should be a warning to any House Democrats who supported health care in November and are thinking about opposing it now.
Although there are plenty of other reasons for the unpopularity of Lieberman and Lincoln, the most recent drops in their numbers are a result of aggravating everyone with their machinations on health care. They ticked off Democrats by watering down the bill and they ticked off Republicans by voting for it anyway. Their 'have it both ways' approach had the ultimate effect of making everyone mad at them.
The health care bill is certainly not popular and there are some Democrats who would probably be better off from an electoral standpoint if they'd voted against it in the first place. But they're going to be better off politically if they stick with their first votes- the Republicans are already mad at them and they're going to be mad at them even if they change their minds. They don't need to get their own party's voters unhappy with them as well. House Democrats who take the wishy washy approach may end up with Lieberman/Lincoln sorts of approval numbers.