HTML Validation
Html 4 Strict is the only doc type for me at the moment because I'm strict when it comes to HTML.
CSS Validation
CSS is the best invention since sliced bread, there is nothing like seeing code validate first time around.
Link checker
A very useful tool when checking for dead links and great for ensuring that your site is up to date.
HTML5
I am super excited about HTML5 and can't wait for it to become the norm. Go HTML5!
WWW Consortium
I think that the WWW Consortium are doing a great job. Now if only they can do something about IE.
W3 Schools
W3S is by far the most useful resource out there and for that they get my support and thanks.
Open Source Initiative
OSI is a great initiative and although I have not used them much I feel they deserve the support.