Did you ever really watch this show? Oh yeah, it's campy as all-get-out but you know you can't resist it. And once you get past the camp you'll see that Star Trek really does have some great stories ranging from the unintentionally funny to the truly inspired. While later series have improved on the formula, the original series has a spirit all it's own.
I forgot to mention that it's also super sexist towards women. It's horrific but also entertaining. If it were the other way around it would be unwatchable for me.
Star Trek was ahead of its time and responsible for developing an interest in space and science for many kids. Still a classic after 40 years! Cons: Even though the story lines may have been cheesy, it was the 1960s!.
The series that started it all. Between it's political allegory and clever science fiction, this series helped push the idea of popular science fiction. The characters are filters for later series. Cons: No one is going to talk about the realistic sets or shots of the ship(remastered edition not withstanding). The science in the science fiction is also fairly moot by todays standards.