Just came back from a conference in Vegas, and my comments -
most of the people there would be just as happy to have it someplace else. Its very expensive (well, where we were), and just 'too much' to see in a couple days, and you wear yourself out trying to.
I'm not looking forward to going back there again. I'd prefer something more mid-country and accessible to more people. Although, SF does sound intriging.
But, again, if you want warmth in the fall period - Orlando could be fun.
I just really don't want to go to Vegas again.