Well, everyone has chosen Firefly here so I’ll go against the obvious with-
All the Star Trek sequel series started with an average first couple of seasons but Enterprise was never really given a chance to shine. Maybe it’s because DS9 and Voyager both started while the previous show was still going strong whereas Enterprise was out all on it’s own but the audience just didn’t give it the chance to get better that they’d given to DS9 and Voyager. Seasons 3 and 4 were really good, but unfortunately by that time people had stopped watching and it was cancelled just as it was beginning to show how good it could be.
I was one of those that really didn’t mind the original opening theme that much, but this is what it should have been –
And here’s the original-