Adventure titles:
(no particular order)
Leisure Suite Larry
Pretty much love the whole series except for the travesty of the newer one. They were immense fun and had fantastic humour.
Curse of Monkey Island
Again, I love the entire series. Well...except for the 4th game but...whatever. The first three were genius and were ground breaking in the genre. Awesome. I'm currently playing Tales of Monkey Island (being released in chapters) and I highly recommend them.
Broken Sword: The Shadow of the Templars
Yes, I enjoyed the sequels of the Broken Sword series but nothing ever topped the first game. I remember getting it for my Playstation and bunking off school to play it all day. Probably learned more about the world from that days play-through than I would have at school anyway. A truly epic game that will take you around the world chasing conspiracies and ancient cults and make you believe it all.
Grim Fandango
I have absolutely NO hesitation in heralding GF as the single greatest game of ALL TIME. It's just totally fucking flawless. You don't get entertainment anywhere near approaching this any more. Manny Calavera will always be close to where my heart used to be (in-joke for GF fans)
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Intimidating? Me?
Seriously. It's fucking amazing. The story is the best you will ever see and the atmosphere, characters, setting and voice acting are just insanely good. If you haven't played it then you're missing out BIG TIME.
Discworld
Rincewind. A seriously inept Wizzard. If you like Terry Pratchet and the Discworld series you're going to like the game as well. Simple as that. Another fantastic adventure from the golden age of adventure games. I miss the old days