Resources

Heres a bunch of resources that i've found useful, all providing the tools and information needed to really get stuck into HTML5 right now.

Documentation

W3C HTML5 Web Author View

Lightweight version of the W3c spec, perfect for web developing and learning about HTML5 features from basic to advanced.

Safari Dev Centre with HTML5 Guides

Excellent WebKit-oriented development documentation, with videos, code libraries and tutorials.

WhatWG Web Apps HTML5 Specification

The working draft spec of everything that is part of HTML5, it also houses information about what is NOT part of HTML5, very useful to say the least.

The WhatWG Blog

The WhatWG Blog houses lots of useful snippets of information linking to HTML5 news and resources, helping to keep an up to date insight about whats going on.

Dive into HTML5 by Mark Pilgrim

A wonderful set of articles about HTML5 (can be bought as a book) containing numerous examples and guides.

Mozilla Firefox Developer Centre

Contains numerous HTML5 demos and guides in a well laid out format, going from beginner to advanced.

Opera Developer Centre

A brilliant set of tutorials and articles about all things web, not just HTML5.

Development Tools

Modernizr

Modernizr is a javascript library for feature detection of HTML5 helping a developer to control fallback cases when building sites and apps.

Boilerplate

A set of HTML/CSS/JS templates with best practices for HTML5 and front-end development built in.

HTML5 Shiv

JavaScript shiv for IE to recognise and style the new HTML5 elements.

Let's make the web faster

There are many variables that affect a site's performance, this site provides a complete list of tools related helping your site 'speed up!'.

HTML5 Rocks Playground

An area of Google's HTML5 Rocks site which is great for trying out with the different features of HTML5, providing Debugging so you can mess around until your hearts content.

The HTML5 Test

This tool upon loading in a particular browser scores it based on what features of HTML5 it supports. Very useful when testing for cross-browser features.

JSBin

JSBin in it's basic form is a big playground where you can go and mess with javaScript on the fly! So it's fantastic for experimenting.

Community and Demo Sites

HTML5 Doctor

A great web site run by a number of brilliant writers and developers, it offers a large range of articles and tutorials with tons of examples!

HTML5 Rocks

A site built by Google to teach and provide a platform for learning about all things HTML5, open source too!

Chromium HTML5

A site for web developers who are interested in using HTML5 and other next-generation browser features available in Google Chrome, Google Chrome Extensions, and Google Chrome OS.

Chrome Experiments

A great showcase for creative web experiments, made by talented artists/programmers. The vast majority of which are built with the latest open technologies, including HTML5, Canvas, SVG, and WebGL.

Test Drive IE9 Demos

HTML5 Demos by the Microsoft developer team, specifically focused on what can be done with IE9.

456 Berea Street

A site built by Roger Johansson with HTML5, covering all sorts of different front-end related topics including HTML5.

A list Apart

A list apart is a online magazine that "explores the design, development, and meaning of web content, with a special focus on web standards and best practices." They have tons of stuff about HTML5, great for learning!

HTML5 Demos

A cracking HTML5 demos site built by Remy Sharp, really useful for finding out more about the different features of the specification and how they can be implemented.

Reference

When Can I Use...

Compatibility tables for support of HTML5, CSS3, SVG and more in desktop and mobile browsers.

Chrome Implementation Status

How up to date is chrome for HTML5? Find out here.

HTML5 Readiness

A visual representation of HTML5 browser support over the last few years.

Web Designers Checklist

This table-structured checklist features both CSS3 and HTML5 specifications; it has web browser support tables for the new HTML5 Audio API, Video API, Web Forms, and more.

B's Web Resources

This well structured site has a large number of HTML5 based tutorials and demos to get you started.