Yeah, I like Lee Child too. Good, uncomplicated kick-ass fun, lol.
Michael Connolly is another great one to get into.
I'm currently reading the new Dan Brown, Inferno, cracking read so far, back to his early days form.
John Grisham, of course, is practically a classic these days.
Again, for uncomplicated fun, Dick Francis is always good to fall back on, even if you're not into horsey things.
Away from the thriller/murder/court drama themes, Cecelia Ahern is a fabulous "girl" author, but not stupid-girly, well written, and often thought provoking (she wrote the book from which the film was made "PS: I love You") and Marian Keyes is another one.
(Now, you know what the "Bookie" is short for, lol).
If you PM me your Kindle e-mail address, I can send you a few e-books to add, that will give you a variety without costing you anything!