S.L.
James Patterson is a great author, if you've not read "Kiss the Girls" its a book I just couldn't put down. I have read almost every Patricia Cornwell novel out there, at least all of the ones I know of, and have really enjoyed her.
I myself am a big Koontz fan, I own at least half of his books, but I think his earlier works are better than some of the newer ones he puts out. Tom Clancy really is my all time favorite, I own every last one of his books and have read all of them at least once if not twice. He and Cornwell both have something in common though, you almost have to read his books in order from the time they were written to be completely up to speed.
Enjoy!