Paul Graham is an essayist, programmer, and programming language designer. In 1995 he developed with Robert Morris the first web-based application, Viaweb, which was acquired by Yahoo in 1998. In 2002 he described a simple Bayesian spam filter that inspired most current filters. He's currently working on a new programming language called Arc, a new book (probably) for O'Reilly, and is one of the partners in Y Combinator.
His essays are well thought out and well written.
How to Do What You Love
What I Did This Summer
What You'll Wish You had Known
and then keep an eye out for Paul's next essay. It will be a good read!