Vegas has my vote because the round trip flights would probably be the cheapest for everyone, sounds like a hubby or two would enjoy going there, and I haven't been there since I was a kid -- bet it would be more fun now
SF is my second choice -- more expensive, but it is so beautiful and there is so much to do there.
Reno/Lake Tahoe is choice #3 -- airfare deals, though probably not as good as Vegas, Reno is fun, like a mini-Vegas, and Lake Tahoe is absolutely stunning...