'Amelie/Delicatessen' are so imaginative.
'The Princess Bride' - I watch it every single time I don't feel well... it's the perfect medicine!
'Wonder Boys' for its magnificent script.
'Wallace and Gromit: Curse of the Were-Rabbit' makes me happy. It really is that simple.
'A Fish called Wanda' doesn't need a reason to be on this list.

Horror: Halloween series (excluding part 3, which sucked)
Comedy: anything with the 3 stooges
Drama: the godfather series
Action/Fantasy: the Lord of the rings trilogy
anime: anything by Hayao Miyazaki
Sports: any of the WWE wrestlemanias

Movies I never get tired of
 

Monthy Python and the Holy Grail
A Knights Tale
The 40 Year Old Virgin

Rocky - A fantastic soundtrack, and fantastic acting to match. I watched this for about the 50th time last weekend, and I probably will watch it again at least twice before the end of the year.

Rocky II - The same reasons as the first. Everything in this movie just seems right. In other words, it's the perfect sequel to an amazing film.

Die Hard - I could remember most of this movie when I was 7 years old. Action from start to finish.

Jurassic Park - One of the first movies I ever saw. Simply breathtaking then, simply breathtaking now.

Terminator 2 - Judgment Day - Another one of those movies that I could remember most of the dialogue from, and still can. Has some of the most amazing sound and visual effects I have ever seen. The cast was perfect too. Arnold Schwarzenegger and Robert Patrick contrasted each other perfectly, and the relationship between Linda Hamilton and Edward Furlong was perfect as Sarah and John Connor.

Dumb and Dumber - So stupid it's hilarious. I never get tired of watching Harry and Lloyd fail at everything, yet still come out on top. And who can forget the cop and the beer bottle of piss....

I can't get tired of Transformers - The Movie (1986)

- Die Hard seems like a popular choice, and I'd have to agree with it. Awesome awesome movie.
- Terminator 2 as well, it has to be another staple that just doesn't seem to age over the years.

Here are a couple of picks I haven't seen:
- True Lies is Arnold at his best.
- Predator is another top dollar Arnold film. Lots of memorable lines, and a very cool chain gun.
- Aliens is still great after all these years. That scene where the cyborg plays the knife game still freaks me out.
- Happy Gilmore always makes me laugh.
- Evil Dead Army of Darkness that last scene with the she-bitch is something I can watch all day.
- Ace Ventura: Pet Detective is another one of my favorite comedies that just doesn't get old.
- Demolition Man is probably my favorite Sylvester Stallone film. Completely over the top, but it works.
- Robocop feels a bit dated these days, but I still love it.
- The Rock has to be another one of those films you can keep re-watching over and over. Sean Connery is uber cool in it. I'd also say Con Air, because I loved John Malkovich's performance but I know a ton of people hated that one.
- Scarface has got to be somewhere on the list.
- Lastly, I'd have to add Heat. Its robbery scenes have been imitated so many times now I've lost count.

Action: Terminator 2
Adventures: Indiana Jones 1 & 3 (Temple of doom is a f*cking crap)

Well said.

Terminator 2 definitely for me. I used to watch it on a daily basis and never grew bored of it.