The SEC will not go with another Texas team as that would immediatly dilute the A&M move. My top candidates for the SEC would be schools that will expand the footprint of the conference and not step on the recruiting toes of existing conference schools. That eliminates Texas schools, FSU, Miami, Georgia Tech and Clemson. My top bets would be:
Virginia Tech- Pros- great program, fertile recruiting area. Cons - not a large city school but decent TV draw, politics as the legislature forced the ACC to take Tech.
NC State - Pros - school may be interested in getting out of the shadow of Duke and UNC, great TV market, great facilities, natural southern rivals w/ USC, Tennessee ect...Cons - political pressure to stay in ACC.
West Virginia - Pros - great program, no political baggage. Cons - small TV market.
I honestly think NC State is the perfect fit both from a geographic and media standpoint, if the politics doesn't bog down the move.