Oh man. That's a question in itself isn't it? There are so many that I have clocked up over the years, I think drama , dance, sci-fi, dreamlike, dark & horror are my most favoured themes I guess , but i am going to say 1 of my most treasured is Menace II Society , Get On The Bus, & Phone Booth. I'm going to mention Under The Cherry Moon & will add Breakin too. Breakin . probably not Breakin 2 [ electric boogaloo ] Just the original makes a big impact for me.
I'm gonna mention Crank too. Also, I liked some John Travolta films the more earlier than later. So. The Boy In The Plastic Bubble , I found him cute probably not a reason to like a film LOL I like Gia, I like Leon. I liked They Live. I like Sleep Away Camp. I like V for Vendetta . Natalie Portman is a cool actress. I like No Men Beyond This point. And i do like fame and other dance films. It depends.
I like some dark rom/period films like Bright Star, Phantom Of The Opera, Wuthering Heights. There are a couple more but I can't remember offhand.
I like most musicals.
The Back to The Future franchise has my vote, people ! ~

Very strong characters & the who , when , what , why are even more explained in the novels. I loved Marty Mcfly & although i support michael j fox in many of his other films I have to say I loved his character in this film very , very much.
Then
The Imaginarium of Doctor Parnassus.. and i will mention Legend [1986] too . Not a big supporter of Tom Cruise at all but I loved where this one film takes me. I liked This is Spinal Tap. I liked SuperBad. Some of that stuff is fun. Some Johnny Depp characters are cool too. He has alot of filmography behind him. I like his Edward Sissorhands and maybe Benny. I like the Home Alone franchise,
Then there is ET, Star Dust , Skyline, Drag Me To Hell, I'm going to include MoonWalker here too. I might just include District 9 ..Yeah i'll include it. I'll add terminator 2 for sure.
I think one of my most 'recent' phenomenal films of all time would be The Cabin In The Woods. I love the motorbike/invisible wall scene!!!!!!!!!!!!!!!!!!!!!!!!

I like most arthouse titles mostly directed by Andy Warhol

& out of Paul Morrissey/s mind came Heat, & Flesh which is okay

But I adore Trash cause again , the character the film provides, Joe Smith, I really felt for that guy..
& of course I love almost anything that comes out of the beautiful David Lynch's mind. Dario Argento is another for me. Okay, but his Demons 2 does my head in if not the visual , it is the
sound and the atmosphere of that film.
And there is much more but those are the main thoughts for me when upon this topic. Many mid - late 80's/early 90s films come to mind. I suppose , pretty much in the horror area really. that and way out there fantasy . Some late 80's horror though can freak me out! I am not keen on the second Trolls film and some of those sounds from the early 80's are a no. Oh , and the Rob Zombie franchise was okay. I liked SAW concept , The first three maybe & I liked The first two or three Final Destination franchise. See i can go on ..