If you want entertaining, not too challenging stuff the following are great holiday reads:
Mitch Rapp series by Vince Flynn
Jack Reacher series by Lee Child
Myron Bolitar series by Harlen Coben
Alex Cross series by James Patterson
Harry Hole series by Jo Nesbo
Camel Club series by David Baldacci
King and Maxwell series by David Baldacci
For something British:
Tom Thorne series by Mark Billingham
All are action/spy/military/cop type thrillers. That little lot have kept me going for a while.
I’d suggest picking one of the series, google for a list of them in order and start at the beginning.