This page will be constantly updated to provide valuable links for web developers and maybe some other relevant resources later on.
Standards compliance
Thought I should include some web-standard checking urls' here.
CSS Validation
XHTML Strict
W3 Web Content Accessibility Guidelines
WebDeveloper plugin for firefox
An absolutel must-have if you are into web-design -> Web Developer plugin developed by Chris Pederick. It adds a toolbar with various web development tools in there.
Site hosting
There are a lot of good hosting providers out there. What you need depends on what how many websites you need to host, storage and bandwidth space, whether you need linux or windows based database support, does speed and uptime (shared vs dedicated) critically matter to you, customer support, reliability, performance and scripting languages supported are the most important parameters that should help you decide.
IX Web Hosting leads the pack currently when it comes to all these parameters plus user feedback. You can host upto 8 domains with them using a single account.
I'd go with DreamHost if you want to host more number of sites without having to pay extra for hosting additional domain names. This is only for starters and those who want to test how website hosting works. Their storage is in terms of 150+GB and growing and bandwidth in terms of TB, unlimited users and databases. For a developer, this is ideal for setting up as many sites as required while in development and testing phases, before moving the site live. As you get more familiar, you may want to switch hosts.
http://www.hosting-review.com/ is a good place to start researching other hosts. More on this for later.
Comparison of CMS
http://www.cmsmatrix.org/ has comprehensive comparison tools available to help you decide which CMS is the best. It will be good if you have a fair idea of which particular content management systems you like before checking that out though or you might end up being overwhelmed by the sheer number in there. My suggestions include joomla and drupal. WordPress is good for maintaing blogs alone.