From an article on espn.com regarding the Big 10 hiring a firm to look into which school which would help them the most in expansion:

"They [research firm] basically broke down what they [expansion candidates] would bring to the table," Wisconsin AD Barry Alvarez was quoted as saying at a meeting of the Wisconsin athletic board. "They talked about academics. They talked about size. They talked about size of their arenas. They talked about attendance. They talked about the populace in that specific area."

The one in bold is the one that I think most conferences will see as the most important and the only one that a University cannot fix or imporive upon.  This reason alone is the reason why I believe UCF, FAU and FIU will all be in the Big East eventually.

I agree!

And also AD Alvarez concedes that the Big11 expansion may not be to one additional team. I truly beleive that the move will be for all of the AQ conferences to expand to a MINIMUM of 12 teams each and up to 16 teams. They are trying to head off the end of the BCS by including more schools (a bigger majority) and by implementing conference championships in each "superconference" (have to win your conference to get into BCS championship game).

I agree GeorgiaOwl....forcing teams to have a championship game is a defacto playoff, and including all or nearly all the teams in FBS in BCS conferences takes away most of the underlying unfairness of the system, quieting critics.

Please pardon my cynicism, but I think one thing trumps all rivalry, stadium, arena and other factors: That one thing is money. Ultimately, the decisions are business decisions, not athletic decisions (though athletic factors are involved). If revenue studies show that FAU can open two new and significant markets to a conference  (through attractiveness of the Owls or of the conference's other teams, or a combination), FAU will get good consideration by someone. However, if revenue studies show that the Owls generate only a ho-hum amount of enthusiasm in the two markets, FAU will be far less attractive.