John Grisham. I love his legal thrillers. I've read every one I can get my hands on. I've been reading his work for somewhere around 30 years now. His novel A Time to Kill is one of my all-time favorite thrillers. It was also made into a pretty spectacular movie, as were many of his novels.
If you love thrillers and haven't given Mr. Grisham a try, I can only tell you that you're missing out. His novels about baseball and other topics aren't quite as good, but his legal thrillers are absolutely the best out there.