My official list of awesomeness goes as follows (including arbitrary number values):
KQ6 - 10
It's my favorite of the bunch. The Realm of the Dead and Isle of the Sacred Mountain just push it over the edge for me.
KQ3 - 9.5
I really, really enjoy this game. It keeps you on your toes. I also, for some reason, actually liked typing in all those spells. There's probably something wrong with me.
KQ2 - 9
This result is highly skewed due to nostalgia. It's my first King's Quest and my first computer game ever. I love this game. Without the nostalgia, I would have it above KQ7. Even though it's knocked for being very similar to KQ1, I do feel it improved on the formula in all areas. The graphics were improved, the parser interface was improved, and the story was improved.
KQ4 - 9
Just an all around great game.
KQ5 - 8
It's a great game with fantastic music (the best in the series, I think) but it does lose a point due to how long it kept me in the forest trying to figure out how to open the pouch and make an emerald trap. And because I just always enjoyed playing KQ4 a tad more than 5.
KQ7 - 6.5
I really did not care for the cartooniness of this game. Or the uptight, yet whiny, Valanice voice or the valley girl Rosella voice. Like, did you hear her? Gag me with a spoon, for serious! Gah! But it was still a fun game. Even with the song at the beginning.
KQ8 - 6
I really enjoyed this game, for all I knock it. But it just doesn't feel like a King's Quest to me. Yes, I know it is a King's Quest, but I just feel that they missed a lot of opportunities to tie the game in more with the series. I've posted my feelings in some other topic, so I'll just leave it at that.
KQ1 AGI - 5
I don't care if it did start it all. I don't really enjoy playing this game. Also, my family never got a hold of this game until we finally got a better computer and the King's Quest Collection, so this game doesn't even hold nostalgic value for me. It's just a very flat game because I know how much even the second game improved on everything this game was.
KQ1 SCI - 3
This was just unnecessary. It didn't even have the benefit of being in VGA like the cooler, but still completely unnecessary SQ1 remake. I disliked the lightened tone of the story (goofy sea snakes in the moat and the Graham shaped hole in the ground when you fall off the beanstalk.) And if I ever, and I mean EVER, find the person who replaced the easily navigated mountain stairs with that abomination of a ramp (and then had that stupid dwarf run up on you as you tried to navigate them) I will not be held responsible for my actions. There is not one thing I like about this remake. No exaggeration. Not a single thing. Even the graphics just don't impress me much, even as an improvement from AGI. At best, this game just exists for me. At worst, it has that ramp. That ugly, idiotic ramp that I somehow always think will actually be more easily navigated than the beanstalk (which is also more difficult to climb) on the way down.
As for the unofficial games, I don't feel like ranking them because, well, they're unofficial. No matter how good they are, they're not part of the official universe. Besides, it's more complicated than just assigning a number. For example, I really enjoyed KQ2+ but they did things I have a major dislike for. I don't like all the Father nonsense, and vampires are never, NEVER heroes. Stake all the blood sucking parasites, that's what I say! I'm on Team Van Helsing!