Ok, I'm going to break the rules slightly and offer up this fan-version of the recent
Thundercats series opening done as if they'd done a proper full opening, showcasing the fantastic animation. The audio is apparently from a Spanish dub, so there is an annoying Spanish overdub at the very end, but the rest of it is very well done:
http://youtu.be/TM-je_ZzWlQ
For a "canon" TV opening, I'll offer the
GI Joe opening from the season after the movie (which is the one did FOR the movie):
http://youtu.be/ok-DrfFJAgw
They just don't make 'em better than that!