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)
