Are we basing this on the current quality of the team of the location's ability to sustain it.
Seattle and Jacksonville are good choices in both categories.
I think Green Bay will one day lose it's franchise to a larger market but it will take a long, long drought and "laughing stock" status for that to happen.
Baltimore is in an over populated NFL market and Tampa Bay lacks mass appeal.
Picking just one, I'd say Jacksonville. Putrid team, crappy uniforms, short history and the 3rd of 3 teams in Florida.
Buffalo fit's the the above criteria except they have a bit of a history.
First of all, this is an absurd argument. One team is eventually going to move to Los Angeles, sure, but the NFL isn't oversaturated. Contraction is the last thing on the NFL's mind. Maybe--although I personally think this unlikely beyond a team or two--some will move to international markets, but there aren't too many left in the U.S. that are better than the ones they have (outside of L.A., of course).
Green Bay will never lose its team. First, it has the entire Wisconsin market to itself. Because of history, pro football means more to the people of Wisconsin than it does to say, Michigan. Also, Green Bay is publicly owned. It doesn't have a single owner that would follow the money anywhere.
Buffalo has an old owner, with an old stadium, and it tries home games in Canada. Buffalo has history, sure, but much less so than Green Bay.
Cleveland is also a silly suggestion. Of all places, the NFL wouldn't let the Lerners or anybody else make them look silly by moving the team again.
Seattle has great fans. They sell out games. Also, it has a region. Lots of teams, especially outside of the eastern seaboard, operate this way. New Orleans couldn't work without the Gulf South. Denver is hugely popular because it owns the Mountain Time Zone. Seattle has the Pacific Northwest. Kansas City must have some significant Great Plains support.
Jacksonville, however, and even Tampa Bay, are squeezed by the saturation of the Florida market. Lots of people live there, sure, but a lot of them aren't from Florida. They bring old allegiences with them. Miami probably has the hearts and minds of most Floridians because it--although not significantly better lately--has some winning tradition and is based in a sexier city than Tampa or Jacksonville.