West Virginia Democratic senator Jay Rockefeller isn't going to run in 2014.
The senate is shaping up to be a really, really tough challenge for the Democrats in that election. They're defending 20 seats, including 7 in states that Mitt Romney won this fall. The Repubs are only defending 13 seats, and only one in a state that Obama won. Worse yet, that one is Maine's Susan Collins, who despite being a Republican in a blue state is almost unbeatable. Given that she won in a landslide in the great Democratic year of 2008, I don't see how she can lose in a GOP-friendly off year. (Unless the Teapers knock her out in the primary, which seems improbable but one never knows).
So it won't be surprising if the Democrats lose at least 7 seats, possibly more, and the GOP doesn't have a single loss.
Revenge will come in 2016, though, when the GOP is defending a massive pile of seats, including a bunch in blue states.