I recommend Santa Fe, New Mexico. Lots of cultural and outdoor activities, a brand new convention center, good food, guaranteed sunshine and a relatively central location so people from both coasts can attend.
I love Santa Fe, but would suggest Albuquerque over Santa Fe for cost and accessibility. Santa Fe is very close. There are many nice day trips to do in and around the area. Weather in summer is hot, but dry (usually). Doesn't have the charm that Santa Fe has, but the cost difference is a lot.
SW flies in and out of Albuquerque.
Phoenix would be even cheaper because it is a SW hub. Would only suggest there in the winter.
