I love the Zork Games! I played through all the text adventures of Zork, and every now and then I even replay The Hitchhiker's Guide to the Galaxy.
Later on when graphics were added I liked Maniac Mansion, Day of the Tentacle, the Indiana Jones Games and many more of this kind.
The Journeyman Project Trilogy is one of my favourites as well. My first action adventure was Ecstatica with its unique ellipsoid graphics. The Alone in the Dark Series was quite cool too.
I liked the Thief Trilogy very much, it's fun to sneak behind the guards and knock them out or to use the different kinds of arrows. And Thief 4 is under development!
Although I love to solve puzzles like in the classical adventure games I always had fun with games like Splinter Cell, Halflife, Prince of Persia or Assassin's Creed.