Oddly enough, I have some books I can read again and again, and some that made just as much impact on me (perhaps in different ways) but I've only read once and love them just as much.

Always up for a re-read:
The Bone Collector
Outlander
certain Scarpetta books
any and all of the Sookie Stackhouse books
Twilight (::insert defiant look here::)

Once and it's still with me:
Lisey's Story
The Host
The Dogs of Babel
Odd Thomas

I wish I knew why there was a difference. Thanks for the think. It's nice to use my head for something besides a sneeze-machine for a minute or two. :)