From Sean Trende at RCP:
That said, I think those who suggest that the House is barely in play, or that we are a long way from a 1994-style scenario are missing the mark. A 1994-style scenario is probably the most likely outcome at this point. Moreover, it is well within the realm of possibility – not merely a far-fetched scenario – that Democratic losses could climb into the 80 or 90-seat range. The Democrats are sailing into a perfect storm of factors influencing a midterm election, and if the situation declines for them in the ensuing months, I wouldn’t be shocked to see Democratic losses eclipse 100 seats.
Lots of data and analysis in the full article.