If I were forced to choose?
I enjoy a fair number of sub-genres, but symphonic, power, and progressive are probably my favourites. Orchestral I didn't mention because it and symphonic are essentially the same thing - neo-classical is also face-meltingly awesome. I suppose the main reason I enjoy them is because they (in my view of things) require more talent and skill than other genres, and are more complex. That complexity is really appealing to me, because I can listen to songs like this ten times over and still find new elements to focus on. That, and the fact that the lyrics are mostly understandable and generally have some actual fucking meaning behind them, as opposed to being nonsensical pig squeals.
Yes, it's ten minutes long. You will thank me for this when you hear it in full.
I honestly think that about 90% of my music is made by bands from Finland. And I love it!