If there was one thing you read , that really blew your mind and you wish everyone would read it. You think its the sort of thing everyone should know. If you had a time machine you'd send there books back to your past self
Here's

1) Psychology of adjustment
Its your brain and you should know how to use it. There's a science to how humans function in society , how to memorise things more effectively and how to be happy. Its called Psychology of adjustment.

59 seconds by Richard Wisemann is a really good book with practical tips from Psychology of adjustment.

The user lukeprog has made a series of posts using material from Psychology of adjustment here as well.
http://wiki.lesswrong.com/wiki/The_S...inning_at_Life

2)Christianity

Reasonable Faith by William Lane Craig is the best apologetics book I have ever read. I love the range , depth , rigour and comprehensiveness. More people need to know a reasonable case can be made for the Christian faith.
Tektonics hub - JP's hub on practical Christian issues , particular on biblical social mores should be required reading for ever exegete.
http://www.tektonics.org/practicalhub.html

3)Scholarship and critical thinking

Guide to efficient scholarship
http://lesswrong.com/lw/5me/scholars...t_efficiently/

This is all I can think of right now. I might add more later
Add in whatever you feel like!!