I’ve been reading Joel for some time.  We use his FogBugz bug-tracking software at SocialDynamX.
I often find myself recommending many of his essays on business and software development to co-workers.

Some of my favorites are:

Big Macs vs. The Naked Chef
Don’t let Architect Astronauts scare you
Fire and Motion
How Microsoft Lost the API War
How much should I charge for my software
Making wrong code  look wrong

But his essays are ALL good. Make time to read them all