LisaE, have you read Patricia Cornwell? (Probably a silly question). I love her books, even if Scarpetta is a bit too over-the-top perfect. I love forensic stuff too, though. I also really like Elizabeth George mysteries, which don't have as much to do with the science end but are pretty involving.
My dh has been really into mysteries etc. for a while, but he prefers stuff like Raymond Chandler. He did get me reading Andrew Vachss, though, which are fantastic (if very sad and slightly disturbing) books in the Chandler vein. (i.e. hardboiled tough guy fights crime, but in Vachss the protagonist is a criminal himself-he's fighting people who do bad things to children, mostly.)
I read American Psycho years ago, thought it was pretty blah to be honest. Not much plot, unlikeable main character, which I know is the whole point, but it wasn't a "read it again and again" kind of book. Of course, there are some who think it was one of the most important books ever etc. etc., I'm not one of them, it was kind of throwaway to me. Interested to know what you think.