Dreamfall: The Longest Journey
The gameplay is pretty bad... the normal adventure gameplay is okay, but fairly simple. The main problems come from the stealth elements, which are poorly realized, and the combat, which is completely putrid. It's comically bad. It also makes one of the three characters you play seem completely worthless, as his story is much less fleshed out than that of the other two and all he does is fight a few people.
But what the game focuses on, the writing and story, are excellent. The characters are generally very well developed and sympathetic, and especially in the magical world of Arcadia, often quite funny. Some awkward animations slightly reduce the effectiveness of the dialogue and voice acting which is much more believable than most games. Despite a couple bits like the increasingly cliche creepy little girl and evil mega corporation, the story is a unique and deeply engrossing tale that grabbed me and kept me playing late into the night to find out how it will all end, which unfortunately it really didn't. The game ends on a cliffhanger with many threads left unresolved, and I hope the final game is released somewhat soon so I can see the end. I do know I will definitely be checking out the first game to see what happens there in the meantime.