One of the reasons, though, is very clear to me. Chanukah was the first Jewish holiday I celebrated, back some four (or five) years ago, when I was still celebrating X-mas. My mother-in-law had already begun her change towards Judaism, and she got us to light the menorah as well. In my apt., alone with a little siddur (prayer book) she gave me, I recited the prayers and lit the candles for 8 nights, staying home, sitting on my sofa, doing nothing for the hour or so it took the candles to burn down. There was no religious meaning to me back then, but there was something about the candles, about the way they burned, all in a row, that really soothed me (and at that moment in my life, I needed it badly).
Years later I would learn about the story of Chanukah, what the candles stand for, and what the illumination represents, but at that moment, none of that mattered; all that mattered to me were those candles and the sense of peace they gave me. Sure, after Chanukah was over (or even in the middle of it, if they concurred) I went right into celebrating X-mas without a second thought, but something was changing in me, though it would take another two to three years to fully realize it.
Judaism teaches that all human souls have a divine spark inside them, an innate connection to God. In the great majority of us, these sparks are dormant, subdued by the mundane world, the day-to-day routine, but sometimes, something happens that lights up that spark and turns it into a small flame and then into a roaring fire. To Jews, that that catalyst is the Torah (and my belief is that to all of humanity as well, perhaps not literally as the Torah, but the essence contained therein), and sometimes it can be manifested in as simple an act as lighting the menorah. My whole conversion, I am sure, can be traced back to that menorah I lit years ago, and the sense of peace that it gave me when I had no idea why.
Sure, there are other reasons that can be deduced for my love of Chanukah, like the fact that it commemorates the triumph of Judaism against the overwhelming tide of Hellenism, a tradition in which I was very much into being as I was a product of the Greek model of logic, but those are interpretations for another day. At the core, even today, I love Chanukah because I love lighting the menorah; I love seeing those flames dance all in a row, radiating an aura of peace around them, having memories to that first menorah I lit, and the incredible road it started me on.
As I said, Happy Chanukah.