It'll be San Diego. Jax can't get out of thier lease or they would probably be the best bet. SD has been trying to get a new stadium for a decade now, LA gets all of thier games on TV so there should be some sort of intrest all ready (although I think any team will fail) And it's not that far away so fans in SD would still see all the games on TV and traveling to games (there's only 8 of them) is a possibility.
I got most of this from Mike and Mike in the morning's interview with a sports writer from LA and it made total sence to me. He believes SD will anounce it at the end of this season and play in the Collusium for a couple of years until the stadium is built. Apparently thier lease is up in February.