Best spot in US for a centralized business meeting for people from all states?

Check out Kansas City --should be pretty good in September. KCMO is a surprisingly cool city (was there for a wedding recently).

Actually, as an alternate (re-reading your question): Louisville, KY or Memphis, TN. They're hubs for UPS and Fedex respectively, so the airports are pretty reliable. You may run into thunderstorms in early September, but you won't see more than a couple hours delays at either airport.

Oklahoma City might be an idea. Central location geographicaly, and pricing is very affordable. The airport has just been remodeled.

I wouldn't worry about making it central. Just do it near a good city/airport, maybe LA, since weather will be good. Plus, people like to go there for vacation.

Chicago? It's a hub for tons of airlines and there's lots of hotel options and stuff to do.

I agree with Chicago. I know that's where a lot of national conventions are held because it's the most central, easily accessible city. That said, when you run the numbers for one meeting, what are the total costs for the meeting? One day/night hotel in Chicago, plus flights may be twice the cost of staying somewhere in the south. Plus, there would be the cost of booking meeting space.

I'm not sure if you use Microsoft Outlook, but there's a way to send a message to meeting attendees to have them "vote" on which option would be the best for them. It's called "voting buttons."

I'd narrow it down to three major places and then do it democratically. I'd also consider a fourth option of doing it Seattle, if people are willing. You can leverage your network here to save on the total cost of the meeting, and see if you can get a block hotel deal to save the participants money. Seattle's beautiful in September and the flights on SW are cheap. This of course, depends on where the majority of your attendees are from.

Check out Indianapolis...centrally located and downtown hotels are reasonably priced