I feel Leisure Suit Larry i-iii should be on that list, as well as Jill of the Jungle.
Larry for it's unique puzzles and the 'correct' thinking for quite a few of the solutions, and JoJ for it's very well done 2-d platforming.
I'll admit they aren't quite as good as many of the games on that list, but they are definitely worthwhile games.
Also, there's no goddamn excuse for Zork to not be on that list. It's from the DOS era, and if you have the hitch hiker's guide to the galaxy game on the list, zork had best be right fucking next to it!