Which Senate seats are most vulnerable in '14? (both parties)

[Blue3]

Which Senate seats are most in danger in '14, on both sides?

I know the Democrats will probably have the most vulnerable seats, since this is the freshman class of 2008.

But before we write them off, every freshman Democratic Senator from the class of '06 who ran for re-election WON (I think only Webb retired, and the Democrats kept his seat). So I wouldn't say it's certain that the Democrats lose 6 seats (which is what the GOP would need to have a majority in the Senate, since Biden will be VP until '17).

[Blue3]

On the Democratic side the seats I am most concerned about are:  South Dakota, Alaska, Louisiana, North Carolina and to somewhat lesser degree Arkansas.

So, then it looks like the Democrats keep the Senate in '14 too.

And who knows which "safe" Republicans are replaced by crazies in the primaries, like Mourdock/Akin/Angle/O'Donnell/Miller/etc.

[Blue3]

All the incumbent Republicans are in ruby-red states. Only one who's almost certainly getting a primary (which may not necessarily be successful) is Graham in SC.

There's talk of a primary challenge against McConnell too.