Top 100 all time adventure games list. Suspense killing, spoiler laden Full List (nb: links in full list do not go back to the reviews in the list).
Dead Cyborg has the heart of a text adventure within the body of a 3d engine (youtube trailer). Caveats: donationware - future episodes dependent on donations. burster plug-in required for browser play
Hetherdale is a full scale point and click adventure, for free. Don't forget to use the map option when it arrives in order to travel faster.