I only include film series that have at least 3 films in them & where I like at least 1 film in the series.
The Empire Strikes Back - Tough choice between this & Star Wars but, you know, villains rock the casbah.
The Terminator - Another tough choice but I prefer part ones soundtrack, Arnie villain and Michael Biehn > Edward Furlong.
Aliens - Like above, two 10/10 films for this & the first but an easy choice this time as much as I dearly love the original.
Raiders of the Lost Ark - I'm not a massive fan of this series as I hate Doom & Skull so another easy choice, for me.
Spider-Man 2 - Toss up between this & The Amazing Spider-Man but I really hate the cheesiness of that whole 'cranes lined up for him' scene towards the end of TAS. I've not yet seen TAS2. Plus, I don't think Doc Oc has been bettered yet as a villain in any of the other Spidey films that I've seen.
Predator - I love Predators & like Predator 2 but this one is easy.
The Goblet of Fire - Potter is a 50/50 franchise, for me. I like Chamber, Goblet, Azkaban & Phoenix but I really don't care for any of the others. So it was between Goblet (great word) & Azkaban.
The Return of the King - My favourite film series from my favourite literary series of all time. I, of course, give all 3 a 10/10 but I go King, Fellowship & then Towers. I can't rate The Hobbit series yet because I haven't seen The Battle of the Five Armies. I should be seeing that very soon.
Batman '89 - I used to love the TV series as a child but I've never been too enamoured with any of the films but I prefer Burton's more fantastical Gotham to Nolan's 'gritty realism' take on something so intrinsically daft as a billionaire playboy dressed as a giant flying mouse who goes around punching bad guys for jollies.
Superman: The Motion Picture - 1 & 2 are flawless films, for me, so a very tough choice & I'm not sure that I prefer one over the other. I think I'd pick Donner's part 2 over Lester's, though. Even if the ending is a bit of a mess, which I appreciate can't be helped.
Police Academy - Easy choice.
The Girl With the Dragon Tattoo '09 - I love all 3, not seen Fincher's version yet, but part one certainly flows much better than the other 2. & I much prefer the ending in the first film to the ending in the first novel. The ending in the novel kind of pisses me off.
Toy Story - Like The Lord of the Rings series this is a rare perfect trilogy, for me. I don't think that I prefer one over the other but I'll go with the one that started the whole wonderful journey.
Rocky - I love them all apart from 5 but this is very easy, for me.
Jurassic Park - Easy.
Disney - Aladdin - Robin William's on truly scintillating form. RIP, good sir.
Lethal Weapon - I like them all but I love 1 & 2 but I'd just go for part 1... maybe.
Dirty Harry - Very easy as I'm not a big fan of any of the sequels even though I love the character.
First Blood - I like them all, to varying degrees, but I only love the first.
The Bourne Ultimatum - I go Ultimatum, Identity & then Supremacy. I've not seen Legacy, yet.
The Matrix - I like the series but this one's easy.
Jaws - A perfect film but I'm not a fan of any of the sequels.
Poltergeist - All too easy.
A Nightmare on Elm Street '84 - I love Robert Englund's iconic & charismatic lunatic slasher (I hated Earle Haley's version & film) but even though I'm a fan of the entire series this was also an easy choice.
Friday the 13th: The Final Chapter - This has, for me, the most likeable bunch of machete fodder in the entire series. Great cast.
Halloween '78 - Very easy choice.
Manhunter - I also love The Silence of the Lambs & like Red Dragon but this one has always been my favourite in the Lecter series.
Hellraiser - I can't really decide between the first 2 so I'll just put the first as it started it all. I hated any sequels after the first one, though.
The Texas Chainsaw Massacre '74 - I'm not a massive fan of the series but the classic is the one I'm most likely to repeat view although it is fun seeing Aragorn as part 3s main villain.
Psycho - I'm not a big fan of Hitchcock films but I only enjoyed the first in this series.
Scream - The first is the only one that doesn't make me want to tear out my eyeballs & throw them at the TV screen.
Day of the Dead - I may be one of the few that actually prefers Day to Night & Dawn. I'm not a fan of the remakes.
Evil Dead '81 - I like all 3, not seen the remake, so it's a toss up between part 1s horror & part 2s laughs.
Child's Play - I like 1-4 but I'd go with the classic.
The Good, the Bad & the Ugly - Another toss up between this & For a Few Dollars More but I'll go with Ugly. Great trilogy, though.
Park Chan-wook revenge trilogy - Sympathy For Lady Vengeance - I didn't like Sympathy For Mr. Vengeance & as much as I like Oldboy (I've no interest in the remake whatsoever) the fact is that I love Lady Vengeance, so this was easy, for me.
The Karate Kid '84 - I only like 1 & 3 but, simply put, part one features more Kove.
National Lampoon's Christmas Vacation - Love them all but this is my fave.
Back to the Future - See above.
Ice Age - I like the first 3, didn't like the 4th. Toss up between 1 & 3.
Madagascar - I like the first 2, but not 3, & I much prefered the first.
Mission Impossible - I only like this & part 4 so this was an easy one.
Star Trek '09 - I used to enjoy the original TV series, was never a fan of the others, but the films always fell a little flat, for me, until this one. I didn't enjoy the sequel, though.
Robocop '87 - Not seen the remake but 2 & 3 were, for me, bloody awful.
Crocodile Dundee - Such a likeable character but the first is the best in my eyes.
The Exorcist - I've not seen the second but I'd be very surprised if it trumped the first & I thought the third was dull.
Pirates of the Caribbean: The Curse of the Black Pearl - I saw the third one at the cinema. I wish I hadn't. I don't think that I'll bother with anymore after that travesty.
Marvel - Thor - I'm not a fan of most of the Marvel films that I've seen but I'd probably plump for this one as my favourite.