Whilst I do like Halloween and have been in the US over Halloween more than once I don't find it to be as much of a festive holiday away from Disney. In Hawaii, it was fun, trick or treating around Ala Moana shopping centre that day, it was amazing sitting out on the rocking chairs of the Moana Surfrider, watching the adults, kids and the street party going on in the street, it was just that day. Bit of trick or treating in the Waikiki hotels, but the street was pretty wild as the adults do seem to heavily get into the holiday tool
Christmas would be my choice of preferred holiday to spend in the US. It's a holiday that even outside of Disney is absolutely gorgeous. Shopping centre decoration, restaurant decorations, hotel decorations, even the taxi's and buses playing Christmas carols in the month of December. It is just a magical festive time of year throughout the whole of the USA and one that I love!
So Christmas it would be for me.