Ravenloft's a goody - though it is quite alot different than any other type of AD&D. Planescape's pretty weird too - though if you played PS:T, you know how sweet it is.
My advice, though, would be to do a little creative work and try blending ancient cultures and create your own - remember, improv works really well, so you don't have to chart out every inch and second of your civilization. Try blending, say the Norse and Egyptians - half-dog warriors wielding the spiritual hammers of their mighty god Thor.
