Really interesting thread. Cards on the table - I love all
Star Trek with a passion, but if I were forced to choose, I'd have very little hesitation in taking TOS as my beloved favourite. However, VOY (and its characters) is my number two incarnation of Trek - pretty much for the reasons described by previous posters. The characters just seem more colourful, more fleshed out, and just much more darn fun than TNG's, which they are seemingly often compared to.
I have no problem with Janeway's so called "mood swings" or even bipolar characterisation, in fact, it makes her more human, and dare I say it, more "realistic" than some of Trek's one beat, "mono-personalities".