As I trawl around the web sometimes I come across a useful web development resource, more often I am pointed to them by the excellent community of developers on Twitter, or in blog posts and articles. Here are some of the best, grouped by category and in alphabetical order. Unless otherwise stated I am not connected with any of these links other than as a user.
Complete HTML5 and CSS3 feature detection library (including pre-written tests), includes the yepnope loader to allow conditional loading based on test results. Included tests can be customised to keep the file size down.
Although perhaps less well known than O'Reilly, and a less obvious choice than Microsoft Press, Apress have a number of excellent titles including Illustrated C# 2012, Pro HTML5 Programming - Second Edition, Pro HTML5 Accessibility and Pro ASP.NET 4.0 In C# 2010 4th Edition
Manning aren't a company I had heard of until recently, but that was definetely my loss. With C# in Depth from the awesome Jon Skeet and The Art of Unit Testing , the quality of their books speaks for itself.
Not only do O'Reilly have a reputation as the leading publisher of development books, their store also carries titles from Packt and Wrox. Their standout feature though is the ability to purchase DRM free e-books (usually in multiple formats) of titles you already own - even if it's an earlier edition. This has made me a massive fan.
Not strictly speaking a developer or training resource, but a fantastic way to save articles, blog posts and web pages for reading later. Removing the clutter it makes a great reading experience and, best for all, it's completely free.
I still like to buy paper books to read and have for reference, but even carrying one of these dramatically reduces your mobility, much less an entire shelf! The solution I have found is to keep the paper versions at home or in the office and carry an electronic copy with me on the Kindle. Code samples aren't always as well formatted as they could be on a small screen, but this is more than made up for the fact I have almost fifty complete text books in my shoulder bag wherever I go.
Like having a seasoned programmer reviewing your code, ReSharper spots errors, potentially problematic code, and opportunities to refactor - as well as a range of productivity tools making it easier to work with both front and back end code.
An indispensable tool for .NET developers who support or need to integrate with third party compiled code or projects where the original source has been lost. JustDecompile allows you to view C# source from compiled classes.
The fastest way to validate an entire website for both HTML, accessibility and CSS errors - finding the errors on those rarely visited pages. Simple site wide validation based on sitemap or link crawling. Well presented reports show you everything at a glance.