I love O’Reilly on all kinds of levels.
First, I found as a budding technologist that their books are among the best reference books out there. No nonsense, no condescension. Just information clearly presented by people who know what they are writing about. See the perl bookshelf for an example.
Second, the publisher is a gem who works hard for open access and tries to work with his readers rather than suspect them of wrong doing.
For the last year I’ve been teaching myself XHTML and CSS. Too bad I didn’t know about Head First HTML.