Some of these have been mentioned, but these stand out for me

Programming:

Getting Real

The Pragmatic Programmer

Hackers and Painters

Business:

Good to Great

Start Your Own Business (I knew basically nothing about small business before I started, and it's a good intro)

Crossing the Chasm (good so far, haven't finished)

Technology/Culture:

The Long Tail

The World is Flat

Productivity/People:

Getting Things Done

Getting to Yes

How to Win Friends and Influence People