6600 watts will certainly work, but your gasoline costs may be pretty high. The inverter generators throttle down to match the watt load, which makes them quieter and much cheaper to run than a 12 hp 3600 rpm motor running full out all the time.
I'm sold on the Champion 3100 inverter generator at around $950. Overstock.com had them much cheaper recently--and new customers often get a 10% discount PIN # upon signup. Customer ratings are good, and the company seems to be very customer oriented--especially for a Far East company.