I think I'm a-gonna throw my hat in the ring for KC, but it would have to be May or early June.
Remember, I am the first F2F organizer, so it would be awesomecakes! I could totally get the pretty good hook up on many things, and KC is central to many peeps. It's a great convention town, we have tons of great eateries and bar type places, and I am the queen of party planning. It's not a super-expensive town, either, and we have 18th Street for blues and jazz, the Nelson with the new addition, and the Kemper for art. I know a great little gayish bar that is roomy and boothy (they play host to the local BDSM scene once a month, so people could totally get their corset on.)
Depending on the number of people coming, I even have a house and backyard deck for DIY parties. I can get a shitton of BBQ and other cuisines for the veg oriented.
KC for the casual, fun WIN.