I love this show. The reason it's so low on the list: it got canceled. After a terrible ending in season 5, it can't possibly be any higher. With a cliff hanger as big as that, there's no way it could possibly be above number 5.
And while I won't give any spoilers, I will say this to all those who've yet to watch this: it's amaZhang. But the ending... Just prepare to cry your fangirl hearts out.
This show gives way to a whole new chapter in Camelot. It's what got me interested in all the Nights of the Round Table and King Arthur stuff.
Number 7: The Adventures of Merling