ALA is one of the best web development oriented websites around, with hundreds of greats articles. As I write this they have 650 articles, all of which are great quality.
W3Schools is where I learned a large portion of what I know now. They have great tutorials on almost everything you could think of relating to web development.
The W3C is a great website that has information on the newest web technogies from the origanization that's created the XHTML, CSS, SVG specification, among many other things.
DMYH has a great compliation of web development related websites, so instead of making this list unnecessarily long, visit this site for many of the other web development oriented websites!