I think that Connery movie is "Zardoz", but I don't know if it's as old as all that, so it might not be the one you're talking about. And "Plan 9" goes without saying.
They Live- Rowdy Roddy Piper and Keith David, with the aid of high-tech sunglasses, discover that aliens have already conquered the earth. Best line (spoken in this movie first) "I'm here to kick ass and chew bubblegum. And I'm all out of bubblegum."
Freaked- Not many people know about this one, so it really
is a cult movie. It has Alex Winter (he played Bill in "Bill & Ted's Excellent Adventure", another favorite) as a TV star turned into a mutant by Randy Quaid, who puts him in his freakshow. It's a hilarious movie, full of stupid gag characters like Cow-boy (part cowboy, part cow), the Bearded Lady (played by Mr. T) and a guy with a sock-puppet for a head voiced by Bobcat Goldthwait.
And speaking of him, see "Shakes the Clown", the best damn alcoholic clown movie ever made.