Sage advice. My concerns on SWA is that it is absolutely and 100% tied to the U.S. economy. If or when travel demand starts to slack due to the economy which is now being planned by all U.S. carriers they will have to depend on the U.S. consumer for their survival. With oil at record highs and no slackening in sight the legacies are all going international for several reasons: reduced competition, better yields through the business travelers flying in upper class cabins, the lower dollar is causing many foreigners to travel here on U.S. airlines, etc. SWA can't currently do any of that. AT and JBLU recognize that and are doing their best to overcome their weakening positions through travel to the caribbean and Canada.
I would look to cargo or DAL/CAL right now as my top choices as they are well run and diversifying their flying properly.