OMGOSH!!! I remember that... I concur 100%. I even thought so when I was a kid. -_-
Does it count if only half of it was a cartoon? I found out that apparently they were going to re-do Sailor Moon completely when it got to the US and make it half live action and half animated... The opening of that was pretty bad - worse than the actual dub opening that they wound up using.
http://www.youtube.com/watch?v=PtkVMZA7Qwc
To quote the dude at the end... "Thank you for not doing that!"
I love anime openings, but I've found very few American openings I actually like. A lot of times, it seems like the Japanese actually consider putting up deep and thought-provoking songs for the opening, while we Americans are just obsessed with shouting the name of the show/main character as often as possible.