In the House, I say Republicans 235, Dems 200.
Senate goes 50-50 (counting Lieberman and Sanders as Dems).
Update (October 29): I'm going to have to back out of the 50-50 prediction on the Senate. Can't see the Republicans doing better than 48, counting Murkowski as a Republican. I'll stick with my House prediction.
As for a pre-mortem, if these numbers are about right, I disagree with those who think they are all the result of a bad economy. The primary drivers that the Democrats could not control are (a) regression to the mean after two good cycles for the Democrats and (b) the general tendency for the midterm electorate to be more Republican than the presidential year electorate.
The other major factor is that conservative America is energized, while it was demoralized in 2006 and to a lesser extent in 2008 (although this is part of "regression to the mean"), while the progressive coalition is at more-or-less ordinary levels of unity and energy.
The only way the Democrats could have changed this would have been to govern in a way less likely to anger conservative America. I disagree with those who say this would be impossible, but it would have required not using a once-in-a-generation shot at major legislative change. If the Democrats hadn't pulled off the "stimulus" (mostly liberal wish-list spending) and health care, the conservative base wouldn't be as fired up, and the results would be less one sided. On the other hand, the whole point of political power is to do things, so it may have been a worthwhile choice from the Democratic perspective.
I suspect there won't be much legislation in the next two years, but there may not be a huge blowout between the President and the House either. Just a lot of sniping on the edges, as everyone prepares for the real showdown in 2012. In other words, 2006-2008 with the roles reversed.