You gotta love Irwin Allen. 
The Poseidon Adventure: Not holding up well, at all.
Voyage to the Bottom of the Sea surely went to hell when it became a kid’s show.
Harlan Ellison wouldn’t even use his real name on the one episode he wrote.
A recent upsurge on my YT feed of Close Encounters of the 3rd Kind related videos prompted me to fire up and watch the movie again. Still holds up great in addition to being a massive shot of late '70s nostalgia. The sound design & score is also still easily on my top 10 list.
In the realm of sitcoms, the last time I rewatched The Wonder Years I thought it still held up pretty well. I feel like the fact that it was set in the past to begin with helps it not feel dated even watching it decades later.
The Big Lebowski is as quotable today as it ever was. But that’s just, like, my opinion, man.
Revenge of the Nerds has not aged well. I enjoyed it when it came out, but I tried to watch it about a year ago - a lot of cringey stuff in there - hard to believe we were so open in comedy about some of that stuff back in the day. Sheesh.
I remember loving the series Combat with Vic Morrow way back when it was new. I looked up an episode on YouTube, and it was pretty bad. The sets were obviously fake, the military aspect was laughable, and the stories simplistic.
I tried watching the 1984 Firestarter with a very very young Drew Barrymore and David Keith. Couldn’t get past the opening scenes. It was just really dreadful.
A lot of films hold up very well, going way back to movies like Treasure of the Sierra Madre (1948), and it would be a list too long for a thread.
I’ve watched Breaking Bad three times, and am on the third go-around of Justified. HBO had too many standouts to list.
Though I remember watching these kind of movies, where the basic premise was the harassment (and flat out assault of) women as a kid and thinking “that’s not actually OK, why is this funny?”
Do yourself a favor and skip the re-make.
Though I personally refuse to recognize that Breakin Bad was released long enough ago to count as something that could be rewatched “many years” later 
Tremors is still just as good today as it ever was. The practical effects were well done and are still very believable. Aside from some of the late-80s fashions, haircuts mostly, it could have come out yesterday.
Time After Time still holds up, as does The Seven Percent Solution. Both feature David Warner, so that may be the key.
Krull is so not watchable in this day of CGI.
Yeah, it seems like it was recent, but it started airing in 2008! I’d never heard of it, probably because we retired that year and were moving from AK to OR. I became aware of it when I spotted S2 in the public library in our 'hood and thought “sure, why not”. After the first episode, I turned to my wife, sort of shell-shocked, and said “We need to start this from the beginning!”
Star Trek: TNG is a perennial household favorite on re-watch, and it kind of holds up, kind of not. The plot devices and technobabble seem increasingly ridiculous, but there is moving and expert acting all over the place, and the cast seem to truly enjoy one another, which is a part of the fun.
Simpsons (single-digit seasons only) hold up as well as they ever did. Amazingly funny and well done no matter how many times watched. It’s shocking to watch the really old episodes and realize they’re even older than my underwear.
I tried M.A.S.H. on Hulu not long ago, which my family thought was hilarious and profound at the time. It’s neither, and the laugh track makes it utterly unwatchable now. This is sad! Some other shows of that era are still very good though, particularly Mary Tyler Moore.
Try the YouTube clips where the laugh track has been excised, it will make you beg for the canned laffs.
I found the tv show Perfect Strangers a couple years ago and it’s still as hilarious as when I was a kid!
I would disagree a bit on Cool Hand Luke. Newman is great, George Kennedy is awesome (as always) and Strother Martin is loathsome. At the end, though, I find myself wondering “for what; all of that struggle in defense of man’s natural right to cut the heads off parking meters?”
It’s a movie about rebellion, I get that. Luke does not deserve most of the shit he has to put up with, but he’s not wholly innocent, either. He was being a drunk jerk and got busted. Yes, the Captain of the camp is an asshole, but instead of fighting a system you can’t beat, shut up, do your time, and get as far away from people like that as you can.
I find that many westerns “hold up” because the setting is almost always the late 19th century, so it doesn’t really matter when the film was made for the most part. I think this is especially true for the Spaghetti Westerns, such as those made by Sergio Leone (e.g. Once Upon a Time in the West).
I feel exactly the same about Tootsie, but I it isn’t a movie that I have rewatched. (Once was enough.)
When I was a kid, my folks were given the soundtrack to The Sound Of Music. My sisters and I listened to that album constantly and knew every word to every song. When my parents took us to see the movie, we were enthralled.
It wasn’t nearly as impressive thirty years later when I watched it on TV with my kids. And I haven’t watched it since.