Why so slow to recover?

The US economy doesn't look very good these days. What happened to the recovery that seemed to be moving at a pretty good clip last spring? Here are four theories I've been hearing.

1. It's the Greeks. According to this idea, Greece's sovereign debt problems are creating uncertainty and fear. I'm skeptical. In the past far more important economies have had just as big problems without a notable drag on the US economy (Mexico in 94' , Brazil and Russia in 99', most of Asia in '97). So how did we shrug those disasters off but not this one?
2. It's the debt. This is the idea favoured by fiscal conservatives. The idea is that the US government has spent beyond its means and everyone now recognizes that a day of reckoning approacheth. Thus we save now so we can afford to pay our taxes down the road. Yeah, maybe.
3. End of stimulus. The government boosted demand but now that the stimulus is drawing to a close; we would need the private sector to replace falling government demand with rising consumption and investment. But they're not in the mood. Why not? See 1,2, or 4.
4. Deleveraging sucks. Debt was high relative to asset values and asset values were inflated. So debt was really, really high relative to fundamentals. Now that debt has to come down and there's no easy or fast way to do it. This is the theory that makes the most sense to me. It is complementary with theory #3.