I loved the miniature golf game in Secrets of the Old Clock, although I agree with Jenny that the sewing puzzle could have been left out. Once I saved after the end of each round of golf, it was pretty easy.
I liked the old roadster Nancy was driving, the black-and-white photograph of the gas station that you saw whenever you needed to get gas, the music in the game, etc. I replayed Secrets of the Old Clock recently and it held up very well.
There's currently an unsubstantiated rumor going around that the Nancy Drew game in October (game #25) is going to be set in Greece or River Heights, but we will just have to wait and see.
Egypt would be interesting, Mad (even though Egypt settings have been done to death in adventure games, I do think it would make a good Nancy Drew game).