It's really a matter of personal preference as far as "good" restaurants go, so you'll get lots of different answers. Here are ours:
We really looked forward to dinner at Biergarten, but were disappointed (all 7 of us) at its mediocrity. Never been to Nine Dragons, but most reviews I've read said it had average food for 2 - 3 times what you pay at home, depending on where you live. We happen to love San Angel Inn for its atmosphere and food, but lots of people dislike it. We've never been to Garden Grill but would like to try it someday.
I agree that Marrakesh is exotic and fabulous! Teppanyaki is also very good, but we have hibachi places around here, so we skip it now when we're in WDW. We just tried Le Cellier in November and loved it!
With so many good restaurants, it's hard to decide where to eat sometimes at WDW - we figure trying them all at least once will help us, so I guess we just have to keep going back!