It's definitely my #1. What's been really neat is watching people discover/rediscover it and a lot of them say variations on, "I didn't give it a chance. What was I thinking? This is good!"
Anyway, I love its grittiness, its weirdness, its imperfect characters and tech. I love that the people screw up. Just like, I dunno, real people, yanno?
After that, I'd put TOS (I saw either first-run or first-rerun; I'm almost 52), then the films (both the original timeline and the reboot), then TAS and then VOY and DS9 but only because I haven't really seen either that much. As for TNG, it's hit or miss for me. Sometimes it's my third, sometimes it's dead last. I like Picard but the whole thing seems, in general and Borg notwithstanding, too sterile for me, too easy and perfect. I'm with Q - space is dark and dangerous, but also mysterious and wonderful, but they're busy sailing around in an ocean liner.
Gaahh, and get off my lawn!