The Three Ninjas trilogy > all.

Episodes 4-6 were actually very good movies. They held a lot of allusions that were told in other stories and melded them all together to create movies of epic proportions.

Episodes 1-3 were more half-baked attempts at that, and were only made to appease the generation that never got to see the original Star Wars movies in theaters.

Actually, although not considered a 'trilogy' per se, another great "Big Three" of movies that were created happened to be the Star Trek movies. (I'm referring to Star Trek II-IV) Each of them happened to have a common theme/occurance within each one, which is why I consider those three a 'Trilogy'.

But yeah, Three Ninjas > all.