Don't count on SAT and MSY being toward the top of the LGB list for JetBlue. They don't serve SAT yet for starters. JetBlue has also given a list of cities that are being considered for LGB service (I believe they have three slots left, even after the OAK/SLC/... additions). I believe the BOS area is on that list. If anything, I would expect them to build up FLL next (they will have SIXTEEN JFK-FLL runs this winter, which is way too many, especially with competition from AA, CO, DL, and WN at ISP).
My one concern about JetBlue is the rate they are expanding. They are getting a lot of new birds, and adding a lot of cities. Sure, the economic downturn is helping them right now, but what happens when the economy rises? More people will resume flying the Cartel undoubtedly, which will take business away from JetBlue, AirTran, et al. Also with the expansion, just look at Midway Mk 2. They got too big too fast, and ended up briefly going out of business. Their network now only has BOS, LGA, DCA, JAX, MCO, TPA, and FLL. Gone are LAX, COS, BDL, and I could go on. What won't stop that from going on to JetBlue? They have chosen their markets well right now, but what happens when they have to deal with the fortress hubs. It would be interesting to see what the people of ATL, ORD, DFW, MSP, etc. would do if JetBlue comes into town. My guess is that they would stick (at least the biz travellers) with the Cartel because of the larger network and superior FF programs (Is True Blue even up yet???)
Just my .02