All right, I'm gonna go WAY old school on you guys. Use to watch my brother play Kings Quest games back when I was a little kid. It's one game that got me into this whole gaming thing.
Kings Quest III was pretty brutal for me. I always had trouble at typing the spells in, because you had to be perfect. I suppose it'd probably be easier now, since I can actually type. Either 2 or 4 was pretty hard due to a bridge you could only cross 7 times throughout the game or something too. I still love 6 though because it has an almost Alice in Wonderland type of world.