one movie just came in my mind:

Kung Pow

I know so many people who abolutely hate this movie (maybe because of the shit german translation), but I think this movie is just great.

Best is the fight with the cow ;)

I would go for Johnny Mnemonic (with the wonderful acting capabilities of Keeanu Reeves in a cyberpunk future) or Event Horizon (Hyperspace travel get somewhat more interesting when the wormholes go through hell), but I've actually found an awesomely bad movie that references several Interplay titles (Sacrifice & Giants) as well as Duke Nukem and Baldur's Gate. And features a naked Julie Strain of Heavy Metal 2000/F.A.K.K.^2 fame.
The movie is of course How to Make a Monster from 2001. I highly recommend everyone here to see it, if you really do love good old games.

Pandorum. Everyone I know despised that film. I loved it. Got it for a birthday present, actually, and I liked it so much it got a place of honor: alone on the top of the shelves where it is the first thing a person will see upon entering my room.

The Goonies!

Cus you've got...

Personality!

Casablanca.

Y'know, Casablanca is 17th highest rated movie on imdb.com.

"The Adventures of Buckaroo Banzai Across the 8th Dimension!" To be honest, most of my enjoyment comes from how bad the film really is. The only other people I know who liked it are my brother and sister, and for the same reasons.

Kik Ki Duk's "Spring, Summer, Fall, Winter... and Spring" (original title: "Bom yeoreum gaeul gyeoul geurigo bom").

And I will not explain. There is nothing to explain, as there is nothing to know or to understand.

Yeah, I never understood the hate that film got either as it turned out to be a very enjoyable film. It actually reminded me a lot of Event Horizon (which has also been mentioned in this thread) due to the claustrophobic feel.

Great movie. 7.3 on IMDB, even better on rottentomatoes. I think you'll have to go lower. :P Actually I think your Hot Shots answer works from earlier - as much as I also like them, they definitely aren't as well regarded.

I recently got this movie in a combo pack with "Killer Klowns From Outer Space" and "Spaceballs." I thought it was GREAT! It was bad in that wonderful way that only a movie that knows it is bad and is aiming for the stratosphere of badness can be. Plus, the effects were pretty damn good for the time it was made.

Aliens.

War of the Worlds (the Spielberg version)