Milliways! Infocoms unreleased HHGTTG sequel.

[Prospero]

Yes, for their time, they were the best, hands down. HHGTTG was very rough. I mean, just getting out of bed before your house was knocked down was difficult! Others I liked (glancing over at crowded shelves):

Trinity: a very tricky, non-intuitive game, I liked it too.
Infidel: delightful!
Enchanter Trilogy: my fave of all the Infocoms. It appealed to the looter/packrat in me.
Leather Goddesses of Phobos: Say no more.
Starcross: my first Infocom and one of my faves.
Planetfall and Stationfall: both really fun, funny, and geeky.

I never got through most of the others, what with work and all. It's too bad they painted themselves into a technological corner; I liked their emphasis on good writing in games. Not to mention the general emphasis on fun and humor, which one seldom sees as much nowadays.