We netflixed the 2007 movie and watched it on Monday. It's not bad. Not amazing, but perfectly ok especially for a rental.
It's a kids movie (or perhaps a tweens movie) and you need to keep that mind when you're watching it. There is action, but nobody really gets hurt. Everything and everyone is clean. The villains are of the frequently bumbling sort. The plot is unfortunately quite predictable. Over all it's cute and fun.
If you're a big Nancy Drew fan, I'd expect to be disappointed. I don't think the film is based on any of the books and I gather that the movie isn't really like them. Nancy is 16 and in high school, not 18 and mostly emancipated as in the books. After the film establishes her in River Heights with her canonical friends and neighbors, she is quickly whisked away to LA. Her boyfriend Ned and her blue convertible show up again, but no one else does. I really didn't care, but I've read IMDB reviews written by girls who grew up on Nancy Drew who were pissed.
Imagine a Disney channel original movie with a bigger budget and better casting (but unfortunately not better writing) and you've basically got this movie. If that sounds like hell to you, then skip it.
UPDATE: One thing, the funniest line for me was Ned telling Nancy to "release the lightning" while she's tailing some goons in her convertible. Nancy drives a Nash Metropolitan. There isn't any lightning to release when the car has 42 horsepower and a 0 to 60 time of over 20 seconds.