Welcome to River Heights Fangirl. I am not a Nancy Drew purist--I grew up with the yellow-spine, flashlight covers . Though I really loved reading the Applewood book reprints of the original Secret of the Old Clock and The Hidden Staircase, I preferred the faster conclusions, and more modern (though dated now) setting of the yellow hardcovers.
I read many of what are considered the "original" 56 Nancy Drew mystery stories. A full list with links to recaps can be found here or click on the 'Nancy Drew Booklist' tab above.