The June 13 Washington Post has this analysis by Dan Balz, saying the voters are angrier than usual and that makes the election more difficult to predict. He did not discuss minor party or independent candidates.

It seems likely that every state will have minor party or independent candidates on the November 2010 ballot for Congress, except New Mexico and Washington. Washington’s “top-two” system will almost certainly confine the November ballot to only Democrats and Republicans, just as it did in 2008, the first time it was used in that state.