RexCelestis:
It's very difficult to get a satisfactory live band for this sort of event. GenCon caters to too many tastes for any one genre to satisfy everyone, or even a significant majority. The alternative generic bands, such as wedding bands, work but lack the energy to really be worth the investment. A good DJ, on the other hand, can play things that make everyone happy, even if not simultaneously. The DJ they had last year, while not perfect, played something for everyone at some point in the evening, kept the floor packed throughout the event, was great at taking requests, and was decent at mood crafting. Is he perfect for everyone? No. Is he perfect for anyone? I doubt it. But he, or a DJ like him, is acceptable by nearly everyone which is the best situation for an event like this.
Of course if you just want to make me happy, give a call to Brent Darley in Madison, Wisconsin. Ever since I moved back to Philly I've missed his sets.
I like my women the way I like my swing dancing: fast, loose, and airborne.