Okay, let's do this... I'll probably miss a whole bunch...
Sierra
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Quest for Glory Series (2, 1, 4, 5, 3)
Space Quest Series (3, 4, 6, 1, 2, 5)
King's Quest Series (6, 1, 8, 3, 4, 7, 5, 2)
Laura Bow Series (1, 2)
Gabriel Knight (1, 3) (haven't played 2, but I'm sure it'll be a favourite when I do)
Gold Rush
Leisure Suit Larry Series (3, 2, 7, 6, 1, 5, 8, 9)
Code Name: Iceman
Manhunter (1, 2)
Lucasarts
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Maniac Mansion (DoTT, 1)
Sam'n'Max Hit the Road
Full Throttle
The Dig
Revolution
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Beneath a Steel Sky
Broken Sword
Westwood
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Legend of Kyrandia (3, 1, 2)
Infocom
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Simon the Sorcerer (1, 2)
Planetfall
Bureaucracy
Zork I
Other
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Toonstruck
The Longest Journey
Ankh
Sam'n'Max Seasons (2, 1)
The Secret Files: Tunguska
Operation Undercover: Dual Motives
Runaway 1
The Last Express
Blackwell (2, 1) -- I'm still yet to play 3!
I saw Videogirl mention Syberia. I hated Syberia, but I did play the DS version, so there may have been some things lost in the port :/. It was a bit too reminiscent of Myst for me.
Speaking of Myst, I don't see what people see in Myst/Riven/Uru. To me, those games are full of boring, obscure puzzles with only visual clues and lack any entertainment value. There are exceptions, of course. I thought Entombed was quite good. I don't like classifying them as adventure games too. They're as divergent from the genre as hidden object games IMHO.
okr, I think your summary of the adventure game industry is pretty much spot on. I do wish some German-developed titles (e.g. Simon the Sorcerer 4) were better published outside Germany. I'm looking forward to The Whispered World too. Aside from Telltale, the only other US developer I'm interested in is http://wadjeteyegames.com/ and he's "independent".