I would say I am an avid Nancy Drew fan and have played all 28 games. Recently I replayed a few of the older games.
Other than an antiquated game engine, I really enjoyed them. Especially, The Haunted Carousel and Secret Of The Scarlet Hand.
There is a great YouTube channel run by Michael Gray. Video walkthroughs for all the ND games. He is hilarious in his commentary.
Very amusing and informative. Try his channel and see what I mean. You won't regret it.
http://www.youtube.com/watch?v=3T2uR_gz_vw