Best puzzles overall in one game: Riven
Worst puzzles overall in one game: Runaway
Best single puzzle: The crazy-hard one in Riven with all the animal symbols.
Worst single puzzle: Probably something in Runaway.
Best utilization of action sequences: Fahrenheit!
Best single voice actor in one game: The player of Manny Calavera, Grim Fandango. Mmm, smooth.
Worst single voice actor in one game: The female lead in Secret Files: Tunguska (English version). What the heck were they thinking??
Worst end scene: Dreamfall and Still Life, without a doubt. (Dracula: Origin is pretty high up there on the list as well, but I was so bored with the entire game that I didn't care what happened in the end.)
Best developed "object finding" in one game: Secret Files: Tunguska (along with any other games that use the same system)