I think part of finding a place everyone can afford to go to is not just the physical location, but can you easily get affordable airfare there, If Mayors Income, Tennesee is centrally located ( i know it isnt) but it cost $800, takes three connecting flights, and is a hundred mile drive by rental car, tha'ts worse than making it vegas or some other big place, which might be only $350 on any given day, round trip.
lewlew, motel sixx and myself vote for Eerie, PA. Appropriately named, lots of places to stay/eat/drink/drink/did I mention drink?
I think a location accessible to Zombie-F would be a main consideration, ergo someplace in the north east/New England region.
Maybe you could do a poll. Choose 5 locations (NE, SE, NW, SW and central just for example). Put those cities in the poll and let each person choose which location would work best for them. then choose the location that would afford the highest attendance. You would have to ask people who actually had no intention of really coming NOT to vote.
In all seriousness, and not to rain on the parade but gatherings like these rarely if ever materialize, in spite of how much fun it would be. Too many variables, with the economy being a key factor. We're spread all over the map and there would be a great many people who, for any number of reasons, couldn't attend.
I'd suggest a few "regional gatherings", where members from various geographic areas could get together and meet each other. Even these might be hard to arrange but it would be easier, IMO, to coordinate a smaller gathering and also make it a bit easier(financially/logistically) for folks who really wanted to attend such an event. I'd be up for something in the north east, but can't see myself flying/driving out west or down south. JMO
Another idea then might be to pick a date... and on that ONE date there would be four gatherings... NE, South, West, and Central... and we could all do a video conference to "see" each other! If anything, a quarter of us could all be together at the same time as 3/4's of everyone else!