Wow the new movie is geting A LOT of hate, I thought it was OK, I thought Temple and Crusade were OK too.
Now Raiders was a cool movie, it came out at a time when 'culturally' it ticked a lot of boxes that needed ticking, much like Star Wars did.
Unless based on a previous artform (literature for example) I see it as being pretty tough for any sequel to capture the zeitgeist of the original (it might actually manage to be a better constructed, or even scripted work, but at the end of the day a pure 'movie' sequel is ALWAYS derivative) Lucas can say what he likes about 'grand plans' but we can all see that much like Indy 'he makes it up as he goes along', so as unpopular as it may be, for me it's
Raiders (beyond reproach)
Skull (What can I say, I enjoyed it, Indy for the post Tomb Raider, gamer generation, and as far as I'm concerned 'Saucer Men from Mars' are just as viable as any deity, and NO I AM NOT A SCIENTOLOGIST!)
Temple (Good old fashioned romp, had some anoyancies, but hey!)
Crusade (Enjoyable, but too 'post modern' and ultimately I found Indy became more of a self aware caricature than he was in Skull... still enjoyed it, but by far the least, daft ending as well IMHO)