If Haley Barbour appoints Pickering, Pickering will be seen as an incumbent and have tremendous leverage in the 2008 race which will pick his successor. Micheal Moore, one of the state's most popular politicians, may very well run against him, but Mississippi backs incumbents nearly 100% of the time. That's why our congressional team is usually so powerful for it's small size, because of the seniority system, and the fact that we send the same people back every time no matter what.
If we're very lucky, Micheal Moore will pick up the seat in 2008, and Gene Taylor will pick up Cochran's seat in 2010 (whenever Cochran too, possibly, retires). Then Mississippi would again have a Dem senate team. But that is EXTREMELY optimistic thinking.
But that's about as likely as a Mississippi fairy tale where Ray Maybus comes out of retirment and wins the governers seat once more in 2011.