ZOMG! I was hoping GOG.com would be able to release some more choice Sierra titles and the QFG series is the choicest out of the lot (at least IMHO). I was brought up on these games and sure the humour was heavily reliant on puns (although the worst culprit for that would be the Companions of Xanth) but the gameplay was sensational for the time. QFG managed to be a hybrid of a traditional point 'n' click adventure but with RPG elements. You could play as a warrior, mage or thief and each had different ways of solving puzzles and finishing the game. Best of all, a lot like what Bioware is doing with the Mass Effect series, you could import your characters from previous games!
Definitely a series ahead of its time and you can get all 5 games in the series for less than $10. Not a bad deal if you're into oldschool adventure games.