Once again, anything by Louise Bagshawe, she's amazing perfect holiday reading.
Anything by Colin Bateman, he does these extremely funny books about an Irish journalist - it's humour/mystery/thriller.
For a thriller, try Ken Follett although I warn you it may be hard to pay attention to any loved ones or holiday sights, this is seriously addictive stuff. As in, myself and everyone I've recommended to has stayed up until 5am to finish a Ken Follett.
Lastly, Patrick Redmond is a more dark/psychological kind of thriller, very chilling and another 5am - er.