Epitome of Shaw Bros' "Venoms" films
I'm biased to this movie on account of it was the firt "martial arts" film of any kind I ever saw. But for all the years of searching for the movie to beat it out, I gotta hold a torch for this one. People will say the costumes are cheesy, the choregraphy was stiff, that it's Hong Kong schlock, and lump it in with the crap that gets kung-fu-movie fans laughed at. But I contend that this film is at the top of the heap of what was to follow in the wake of Bruce Lee's death. The "kung-fu movie" became a staple money maker in Hong Kong through the '70s and '80s, and a certain flair the Shaw Bros studio perfected in that period remains superior to anything that has come along since.
Some absolute classics which approach toppling this king of the hill are obvious, I think:
Five Deadly Venoms
Shaolin Master Killer
Executioners of Shaolin
Five Fingers of Death
The modern era of Hong Kong has eclipsed the '70s and '80s beyond the years between- the attention to story and costume and on-screen talent, as well as set design and dubbing quality, has evidenced a totally and thoroughly modern approach to film-making. While so much drek was churned out over those "early years", the Shaw Bros managed to develop a style that set each of their films appart from the crowd- with laughable budgets (by Hollywood standards). You have to consider the era it comes from, with the cookie-cutter formula being the norm, and I think it stands to test against the other "Venoms" films. It has enough of everything which represents the Shaw Studio style that it epitomizes the very best of their output.
While the other films I listed are supreme classics, this one gets my vote for best all-around. Bruce Lee's films, however, are beyond the tag "kung-fu movie", and deserve to be considered above the bar.
I'm just making my case, "What's your style?"