I always thought that VOY had the best opening of any Trek, both in music and visuals.
Yes, this. ^
The opening is simply epic, and the theme is my favorite of all the Trek shows.
Also, I always liked the distinctive ship design of Voyager. It looked like a sleek cobra's head. It seemed to suggest that the ship may be small, but it had a nasty bite.
I'm also a fan of Kes, Seven Of Nine, and the good Doctor.
I admit that I didn't like Janeway at first, but she grew on me. I enjoy the fact that she's a coffee addict, as well as her mother lion attitude towards protecting and fighting for her crew.