Just to take this away from it's heavily LotR-influenced state, here's mine
Rainbow Six by Tom Clancy (who could forget this? It's an absolute classic)
Remote Control by Andy McNab (been ages since I read it, but it's pretty damn good)
Seven Ancient Wonders by Matthew Reilly (great Australian author - I love the sense of adventure in this)
The Last Templar by Raymond Khoury (very good read; I suppose you could call it an action/adventure "Da vince Code"esque book - although I've never read that, it's supposed to be an influnce in TLT)
His Dark Materials trilogy by Philip Pullman (incredibly interesting, great read; definately recommended - although I must admit, I prefered it before the movie "The Golden Compass" came out and ruined it a bit...)