Christmas lights. I have always been a sucker. I'm quite the connoisseur to boot, quick to appraise a home's lights, saying what they've done wrong, and what I like about it. For example, those houses that are decked out in only blue lights? Creepy as heck in my opinion.
Every year growing up, it was a tradition to go see the lights in a neighborhood about 20 minutes away from ours. It's called Prestonwood Forest, in Northwest Houston. Huge crowds would be driving through, and as a child, it was always a magical thing to see. The houses are big, and they use tons of lights. And each street has a theme.
This site here has some history on it, with pictures, and even a video. http://www.chinatownconnection.com/prestonwood-holiday-light-show.htm
My childlike awe of Christmas lights has stayed with me into adulthood. They still always catch my eye, and I get excited to see them. Even when we were house hunting, as we looked at each possibility, I'd envision in my head how we would do lights on the house. The house we ended up with will be a challenge, but it has definite potential to be cool.
Basically, my love of Christmas lights is such, that if we had the money and resources, this would be me: http://www.youtube.com/watch?v=8qc_RYm0ylA