Listmania!
Web Design / Web Development MUST HAVE Books
JavaScript: The Definitive GuideJavaScript: The Definitive Guide by David Flanagan
Buy new: £19.08 / Used from: £14.72
The bible of Javascript. I own the 2002 edition, but there's an updated one
Essential ActionScript 2.0Essential ActionScript 2.0 by Colin Moock
Buy used from: £22.35
Best ActionScript book around. For flash developers.
Don't Make Me Think!: A Common Sense Approach to Web UsabilityDon't Make Me Think!: A Common Sense Approach to Web Usability by Steve Krug
Buy new: £14.94 / Used from: £11.52
Serious about Usability? Get this!
Eric Meyer on CSS (Voices (New Riders))Eric Meyer on CSS (Voices (New Riders)) by Eric Meyer
Buy new: £20.99 / Used from: £19.13
From the CSS Guru. Great resource.
More Eric Meyer on CSS (Voices That Matter)More Eric Meyer on CSS (Voices That Matter) by Eric Meyer
Buy new: £20.99 / Used from: £10.00
It complements the book above.
Programming Flex 2: The comprehensive guide to creating rich media applications with Adobe Flex (Programming)Programming Flex 2: The comprehensive guide to creating rich media applications with Adobe Flex (Programming) by Chafic Kazoun
Buy new: £19.16 / Used from: £4.93
The Evolution of the ActionScript Language. You can now use it on Flex 2.0 and the next generation of Flash.
Programming PHPProgramming PHP by Rasmus Lerdorf
Buy new: £14.09 / Used from: £12.38
Good resource for PHP 5
Professional ASP.NET 2.0 (Programmer to Programmer)Professional ASP.NET 2.0 (Programmer to Programmer) by Bill Evjen
Buy new: £20.79 / Used from: £16.00
Get to grips with ASP.NET 2.0
Build Your Own AJAX Web ApplicationsBuild Your Own AJAX Web Applications by Matthew Eernisse
Buy new: £12.66 / Used from: £6.00
Ajax from the Sitepoint website guys!
Transcending CSS: The Fine Art of Web Design (Voices That Matter)Transcending CSS: The Fine Art of Web Design (Voices That Matter) by Andy Clarke
Buy new: £17.71 / Used from: £16.09
Probably the best advanced XHTML/CSS book around