Flying Circus ran on the BBC between 1969 and 1974 with a feature film titled with the group's favorite segue And Now for Something Completely Different sandwiched midway in its run which took the odd approach of refilming some of their greatest hits without of the presence of a studio audience, the result of which is strangely compelling. The series has many regrettable sketches and running gags, and I feel I should keep my opinion on Gilliam's animations to myself in fear of being shunned, but it is absolutely worth suffering the dreck to get to their best and most outrageous routines (or you could just watch them on YouTube---my favorite bit is Palin's bumbling Spanish Inquisitor).
The gang followed up the series with Monty Python and the Holy Grail, perhaps the most widely seen of their features and what I'd personally consider the best of the lot. This silly take on the Arthurian legend has many indelibly hysterical moments and only starts to come apart at the seams towards the very end.
The controversy generated by Life of Brian, which tells the tale of the child born a manger over from Christ, catapulted the Pythons to international superstardom, but the film offers easy and obvious satire, with belabored gags, and laughs that are few and far between (though those few present are hearty). Gilliam's direction does achieve great period look (though his influence beyond that is distracting) and Palin's Pontius Pilate is unforgettable. Casting Chapman in the lead serves as a great disappointment considering what is lost in the supporting roles.
Time Bandits is not officially a Python movie but it was directed by Gilliam who cowrote the script with Palin and features cameos from both Palin and Cleese. The fantastical and occasionally creepy children's story deals with a band of dwarves in possession of a time travel map who take a neglected youth on their marauding journey through history. The film again falls apart towards the end but the actors are likable and the proceedings are worthwhile for the hilarious cameos, which also include Ralph Richardson and Sean Connery.
Next up was Live at the Hollywood Bowl, a live show converted to film and released theatrically which consists of old sketches and new that comes off quite well leaving you pondering if their material isn't best suited for the stage.
Meaning of Life, which takes a surreal look into each of life's stages, is a sporadically funny feature which is hurt by dark and atypically heavy dosages of cynicism and vulgarity. The short film that opens the movie is a highlight and the "Every Sperm is Sacred" number is priceless.