Blade Runner!

If your new at this genre, i frankly would not recommend you playing this older games. They will feel like work more then fun, unless you can somehow play them on an handheld like the DS or something. And even then, because of the gameplay i don't know. Video games are not like movie or music, they just don't grow old well. They were great in their time but that's gone. I know because i grew up with them, and i recently replayed one of them, and it just didn't feel the same. The magic was gone. I would hate to see someone grow to dislike this genre just because he started the wrong way. I would recommend you play the more recent ones like:

Fahrenheit (One of the best games i played in years, although the end is a bit dumb. In the US it's caled Indigo Prophecy)
Runaway: A Road Adventure (Great. Their's a sequal, not so great but still ok)
The Longest Journey (the sequal is a let down)
Sam & Max Season 1
Syberia 1 and 2 (great and visually beautiful, second not as good, but a must for any serious adventure fan. You have other games from the same autor Benoît Sokal, that are overal pretty good)
Secret Files: Tunguska (great)
Broken Sword: The Sleeping Dragon
Secrets of the Ark: A Broken Sword (not so great)

But if you really want to try older ones i would recommend this ones, because i think it's the ones that best enduer the test of time and are still fun:

Grim Fandango (great)
DiscWorld noir (it's absolutely gread but also hard, your gonna need a walkthrough with this one)
Blade Runner
and some others i can't remember

Too many people I've seen say a blanket statement that games don't age well. It depends on the perrson. I still play old games and absolutely love it. And I know there are others here that do as well. I played the old Zork text adventure just recently. And King's Quest I as well. I still love them. It all depends on the person.

I want to try DiscWorld noir. I only recently learned there were more DiscWorld games beyond the first one.

 It's true, it depends on the person. But I think that the people that still enjoy old games are a small minority (i do include myself in some extend in that group). They're the exception to the rule. Because the vast majority of the people don't. And that's especially true for the ones that only became gamers for the recent years. It's true their are games that are still a lot of fun, like Tetris. But even Tetris had to get a graphic update to keep him fresh. Movies and especially music grow old a lot better than games. Even today when i listen to songs from the sixties like the ones from Bob dylan and others, i enjoy them as much as any song from today. And i wasn't even born then. Hell, i even enjoy the movies from chaplin. The same doesn't happen with games. There's a very good reason for that. The technologies that drives games, changes so fast, that it only takes a few years to make a huge difference between games. And so the age becomes very apparent. Technologie doesn't impact movie and music so dramatically that fast, which makes them not grow old that fast because the differences aren't so obvious.

anybody knows who game is this:

This.

OMG necromancy!

Ragnarok online!

It's a great MMO IMHO!

Just get the updated versions of first two monkey island. They have great visuals in comparison and are fully voiced. 

Grim Fandango is probably the best point and click adventure ever made.

Psychonaughts is amazing aswell.