Oh trout. How the smurf did I forget about the Zork series?! The first few are just text-based, but once you get the Return to Zork they became amazing. My favourite being Grand Inquisitor, and although Nemesis is pretty good it really deviated away from the feel of the Zork world.

In fact, I'd go as far to say that Grand Inquisitor is tied with Riven and Grim Fandango as my favourite adventure games!