Mississippi could be very interesting. If there is one state in the deep south that could make the GOP sweat, it might be Mississippi after the closer-than-expected election of 2012. However, that was with a black Obama on the ticket. With him not on the ticket, that could also swing it back to pre-Obama levels. I'm predicting the latter, but would not be surprised by the former.
The MS poll might actually show a lead for the Republicans, well within 10% or even closer than that (maybe the Southern candidates Paul and Rubio up 5-10, while the Romney-like Christie and the not so well known Cruz about tied with Hillary):
MS is getting increasingly more "black". Blacks account for 38% of the population is MS and they account for 43% of all annual births in MS.
This means the percentage of Blacks will naturally increase until 2016, which helps the Democratic candidate there.
Also, I think Obama's black coalition will also come out for Hillary, because the Clintons have historically been strong with Blacks.