I just saw a Filter episode that lists top 10 adventure games, according to the results of an online poll. This is how it went.
10. Full Throttle
9. Hitchikers Guide to the Galaxy (the text game)
8. Seventh Guest
7. Syberia
6. Myst
5. Leasure Suit Larry (original, not the remake)
4. Escape from Monkey Island
3. Grim Fandango
2. Ico
1. Sam & Max Hit the Road
BTW, who here's played Ico, what platforms is it available on, and what do you think about it? I'm intrigued now.