Vince Flynn writes really good political thrillers. He has such inside political information that it makes his novels all the more real, especially in this post 9/11 era. I would bet a 17 year old boy would really like them. There is a particular order to the Mitch Rapp series.  Transfer of Power is the first one.

Vince Flynn's website:  http://www.vinceflynn.com/

Anything by David Rosenfelt or Harlan Coben

i know you said he doesn't like fantasy, but the drizzt books by r.a. salvatore are great. you don't have to think about it much (well, it is fantasy) but they're fun and entertaining books. and if he loved harry potter, sounds like that's just what he likes. =P if he likes horror, then swan song by robert mccammon is brilliant. it's definitely one of those "it's only scary when you think about it" books, but it does have moments of pure terror. =D or, chuck palahniuk is always great, though it may not be if you like to watch what he consumes. so is irvine welsh for that matter.

and anything r a salvatore and several of the ken follett novels...and dean koontz Fear nothing and Seize the Night were real big hits when they did not care for some of the other koontz. They also liked Clive Cussler for the excitement with humor.

deborah

Another suggestion would be some biographies about people that interest him.  There are dozens out there about sports figures, historical figures and celebrities.

The first four Raymond Feist books (recommendation per my son but I remember my daughter reading them too at a younger age).

What about Carl Hiasson?  I can't remember the exact name of the book (someone help me out here)...might of been called Tourist Trap?  It was set in Florida.  I thought it was very funny and from what I understand many of his books are like this.  I think it might be appropriate for your son.