Matrix

Can't think of any films that others won't mention... but I can think of a couple of TV-series... The first that comes to mind is The Hitchhikers Guide to the Galaxy, it's still a good series (though doesn't quite match up to the original radio versions or the books) but the laser effects and any explosions in particular are hilariously bad. The animations for the guide apparently won an award for TV special effects back then, and while they are nothing special now the style in whicj they were done means they still work well now.

Another series is Farscape.. which is only 10 years old, but often when they strayed from the awesome Henson puppetry there was some bad CGI... such as when they try to make it look like Rigel is walking, or one particular scene where D'Argo slides down a maintenance shaft is laughably bad. (I think it must have been a quick hash together with green-screen tech)

Logan's Run. Great movie!

evil dead 3 had some bad special effects, the skeletons looked fake, loved the movie though

The Dark Knight, and most likely The Dark Knight Rises will have, too

I disagree with some of the movies already mentioned, especially Jurassic Park. 20 years later and those dinos still look pretty damn good and about as realistic as you're gonna get when juxtaposed with real actors and scenery. I'll take that over the crap that is Avatar and Transformers any day.

Also, movies like T2 and Blade Runner still look good too. Blade Runner just has that classic, timeless feel to it, and the only blemish on T2 nowadays is the cheap-looking computer animated T-1000 when he's 100% liquid metal in some scenes, but everything else still looks great... go watch the scene where Ah-nold slits his arm and rips off his skin revealing part of his robotic skeleton underneath. Still looks realistic.

Now movies whose fx haven't held up... Clash of the Titans is an obvious one with some cringe-worthy stop motion animation. It looks like a monster movie straight out of the 50s or 60s. More recently, Independence Day looks totally dated. I remember when it first came out and people were going nuts over the alien ships destroying the Empire State building. Now it looks like garbage.

I liked The Cell, even though J Lo is terrible.Beetlejuice (clarymation)

Who Framed Roger Rabbit. It was mindblowing back then. Looks like shit, now. A lot of the appeal was the special effects (and Jessica Rabbit's boobies). Only Jessica's boobies have withstood the test of time.

The Rocketeer is a personal favorite of mine and it looks pretty bad at times, too.

the first Superman and Batman movies

I remember the rocketeer,although I haven't seen that movie in years.