Okay, you knew I was going to say that. After that, Firefly.
But no, seriously, between the two, Star Trek, specifically TNG, which I absolutely loved. I never got to watch sci-fi while growing up (no one in my house liked it, and I remember once, my brother scoffing at me and changing the channel when he found me watch TOS), so I never really bonded with TOS, but TNG was the best, especially the later seasons. I think maybe I liked the optimistic view of the human race that was the core of TNG and Picard's nobility and interest in exploration, without the preachiness of the later series. (Hm, that's the same reason I love Doctor Who.)
I did see the original Star Wars, and I remember making my dad take me to see The Empire Strikes Back and The Return of the Jedi, but they never caught my imagination and they were just movies to me.
Now, can I get back to talking about Doctor Who? ;)