1. Multi-core processors. We can easily retcon it to say they meant a server room with many processors when they said "computer core", but the fact remains that the intention at the time was that the Enterprise-D had 3 cores. The computer I'm typing this on has 4.
2. Firewalls and isolated, dedicated computer systems. If something got into "the ship's computer", it could get pretty much anywhere. There should have been no way that the holodeck (an entertainment device) could touch the essential operating systems of the ship without someone (like Barclay) intentionally allowing it, and there's no reason any of that should touch data storage or processing for the replicators.
3. Encryption and strong passwords. At the time, the password Data used to lock out command functions in that episode where he hijacked the ship seemed pretty impossible. But knowing how quickly it could be found *now* by a zombie network means it would be utterly trivial for a late 24th century computer system. And it was the most complex password shown. The shield prefix codes seemed horribly silly to me *at the time*, and the simplicity of the destruct codes should have been putting the ship in danger all the time. And the idea that just because Kirk's Enterprise could intercept the Romulan transmission in "Balance of Terror" should mean they could *decrypt* it so easily as to be able to look at the Romulan bridge is absurd to us, now.
4. Socially acceptable relationships and marriage equality for gay people. We *just* had our first apparently gay character. (I mean "apparent" in the sense that we can tell, not to question whether or not he is. Lt. Hawk in First Contact was gay, but there was *no* indication on screen.)
5. Realistic industrial-style robots and other hardware/software automation. This was done almost-correctly exactly *twice* that I can recall - the exocomps, and the automated repair station in Enterprise. In both cases, there was a plot twist, though: the exocomps became self-aware, and the station was part of an evil plot. Never that I can recall did we just see something simple and straight-forward like non-self-aware robots working on damage on the outside of the ship.
6. Wi-Fi. This is a weird one, because it seems like sometimes they did, sometimes they didn't. The tricorders could tie-in to the ship's computer, but Data needed a big honking cable stuck into his head to interface. I know that was partially for the viewers, but c'mon: letting the viewers know what was going on could have been achieved in dialog or by having Spiner consistently do a gesture or other expression in a specific way that indicated he had connected.
