The best books a Tech CEO should read are books that are relevant to being a CEO (and tech). Mike gave relevant advice about technology and Mashable...
A CEO is responsible for the vision of the company to be realized - thus I wild give him the book, "Start With Why" by Simon Sinek.
A CEO is responsible for the people (staff, customers and vendors) that he serves - thus I'd give her "Tribes" by Seth Godin
A CEO is responsible for financial results thus I would give him "Execution: the discipline of getting things done" by Larry Bossidy and Ram Sharam.
A CEO is responsible for the culture of the company thus I would give her "Delivering Happiness" by Tony Hsieh.
There are many great books that one can read on the relevant subjects of Leadership, Culture, HR, Execution, Sales, etc... these are only a few.
It's wonderful to be a CEO of a company but it's a dead end job if the CEO is unable to inspire, lead and achieve measurable results.