Read a lot of Ludlum when I was in the Navy...he was prolific back then, and I guess the time place and style suited my life then, which consisted of long periods of boredom punctuated by frantic moments of chaos, and it was just natural to flow into Clancy's early works.
Vince Flynn I enjoyed a lot, plus being a local guy you kind of felt contemporary with him, but I also enjoy many of the works by Nelson DeMille, Stephen Hunter (the Bob Lee Swagger series), I don't think the latter two have anything new out so I seem to be in a searching mode since the passing of Flynn.