I'd have to say Disneyland. I can see how Vegas would be a bore if you've already been to AC and are from the east coast.
Las Vegas is only fun when you drive from CA doing what we call "a turn-around". Driving 4 hours one way to state line (usually a lil buzzed cuz u could get away with drinking n driving back in those days, no one was on the road) gambling at either Whiskey Pete's or Prima Donna, if it was winter sometimes there'd be snow on the ground (weird huh) and freezing cold with 40mph winds. Then you'd play at the $2 bj tables "holding" the cards single deck actually winning more hands than losing. By then you'd be so drunk you'd have to go outside in the cold to sober up. You'd get in your car now half bombed (still no one on the road) and you would stop in Baker go to the diner there with all the truckers or stop for fast food in Barstow eat then head back home which was another 3 hours. Those were the days.