Astronomy because the universe is just incredible.
Biology because the study of life is also fascinating. I plan to major in microbiology in college, actually.
Oh my there are so many. I love Astronomy, Astrophysics, Physics, Biology, Cybernetics, Archeology...you know what? It's easier to say what field of Science doesn't interest me, I'll just leave it at that
Paleontology, because too many reasons. Been studying it since I was a child and have almost attained the equivalent of a Masters degree in terms of knowledge.
Of course, since I have no official credentials, that all goes to waste in an argument :/
Behind that is pure math. Not a science? Too bad.
Computers; I love technology.
Physics; knowledge of the universe's workings.
Chemistry; knowledge of matter.
Biology; knowledge of life's functions.
Astrophysics; knowledge of the unknown.
I want to go into forensic biology but as far as other branches of science go, it's a toss-up between epigenetics, quantum mechanics, medical science, cosmology and atomic and particle physics...