I think my list would be, in no particular order:

The Princess Bride
Working Girl
Monty Python and the Holy Grail
Young Frankenstein
Officer and a Gentleman
Star Wars Trilogy
The Little Mermaid
And, yes, Dirty Dancing.

I watch these movies enought to post twice it seems.

Also, it might have helped if you'd started as a pre-teen.

Heh. That's probably true. I think I was already over 30 when I first watched it and my main reaction to it was ".... ermm, it's cute." It also strikes me as the kind of movie that's better enjoyed in the company of like-minded people. I watched it by myself after much "you haven't watched it??" from people, so bloated expectation may have also played the role.

Have we discussed this yet? [link]

Alan Tudyk plus Tom and Zoe from Spooks. Looks pretty funny, though hopefully Alan's part won't be too watch from the hall.

I've seen King of Hearts! Mostly because I heard it was similar to Harold and Maude. I remember liking it, but not much else about it.

My favorite memory of The Princess Bride was watching it in India, with a rented VCR and a tenth-generation copy of the movie, with the other Americans in my group. The tape fuzzed out badly at several key parts, which caused much grumbling, but almost immediately we all began speaking the lines and narrating the action that we were missing on screen.

Most watched in a theater in the pre-video era?

The Princess Bride for me hands down. In the 6-odd years I lived in Montreal I probably saw it on the big screen ten, twelve times.

it might have helped if you'd started as a pre-teen

Infant! Some of us were in university when it came out.

I think I need to distinguish between movies I've rewatched for extra-meritorious reasons

David hits the nail on the head because I think My Neighbor Totoro is soaring to no. 1 based on the bits and pieces we watch with my son.

My list of movies I've chosen to watch over and over again would probably be:
The Big Lebowski
The Good, The Bad, and the Ugly
High Plains Drifter (which isn't really a good movie, but it's one that I will watch, for whatever reason, whenever it's on the tv)
Star Wars
The Wild Bunch
Miller's Crossing

Alan Tudyk plus Tom and Zoe from Spooks.

And Rupert Graves! And Peter Dinklage!

Infant! Some of us were in university when it came out.

Sorry. (not really)

When we went to see 28 Week Later last night, there was a queue to be let into the screen showing Waitress. Interesting, given this is the only place I've seen mention of it.

Impromptu

Oy yes! I've seen this one many times too.

Heathers

I bought the sooperspecialanniversary edition because I remember loving this movie to bits. Saw it several times in my younger days. But watching it now ended up being painful. Perhaps it was my mindset in the moment, but it seemed so much more mean-spirited than I remembered. Must try again.

Speaking of Christian Slater (weren't we?) and most watched movies. Another that I must confess to seeing 6 times...in the theatre...in one week...is...wait for it...Untamed Heart.

I know, I know. But...but...I was going through a painful breakup and it was perfect for my mood.

And plus? Kyle Secor as a baddie, Rosie Perez ("I'd do 'im, but ooooh that hair") and the sweetest co-dependent ever, Marisa Tomei ("Magic records and a baboon heart. Now ya got me believin' it.") And, the extra added bonus of the best hockey-game kiss ever filmed.

I couldn't wait for the dvd. It's a guilty pleasure.

I feel so clean for having made a clean breast of my weakness.

You may mock, but don't be hatin'.