Ok, I've gotten a couple of votes for Chicago...
Not only would it save a couple of plane tickets for the couple with 2 weddings to attend next summer, but it's also a central hub for a lot of air travel. I've checked with expedia and it looks like the rest of us could get tickets for around $150 to $200. I checked this from Houston, New York, Baltimore and Austin. If I left any off (I didn't do NOLA), please let me know if it would be any more expensive.
I'm cool with Chicago. I've never been, but there seems to be plenty of things to do. I'm not sure even what attractions may be in driving distance (if we want to rent a mini-van or two).
This is not a final decision, so any other suggestions can be considered.
Another thing we need to consider is what dates (see 2 weddings notice above).
Let me know.