I don't think this stimulus plan will really have a negative effect on Obama. He has tried his best and he has come off good in the media while doing it.
The real turds are the House of Reps. They are the ones who overshot their load with the initial plan and slowly backpeddled into this odd, monsterous compromise bill that no one seems happy with. They are already riding historic lows in approval rating and they are the next up for re-election in 2010. Could be a blood letting.
Nah, the House Reps had a pretty good bill that was in line with what Obama was proposing. Remember that the original version of the Senate bill was more expensive than the House one (because it included an AMT patch).
The problem* is that the people forcing and negotiating the compromise in the Senate seem to be doing it just for the sake of doing it. There's really no apparent logic or empirical basis for what they're targeting. It's a total hodgepodge.
The approval rating of the House overall means very little. It was rock bottom last cycle when the Dems were in control and they won more seats. People always like their local official way more than the institution as a whole.
*The actual problem is that a few dozen Republican Senators and pretty much all the GOP House Reps are married to an ideology that's mutually exclusive with reality. But that seems like such a fact of nature at this point it's hard to blame them. They're too dumb to be moral agents at this point.