As of IE8, we've been able to use counter or increment properties with the :before pseudo elements, or content property.
CSS3 adds names colors from SVG and well as colors defined by Hue, Saturation and Lighness. Below is a table that lists all named colors along with their hexidecimal, RGB and HSL values. Also, check out the CSS3 Color Converter
Border radius, border image and box-shadow are now supported in Firefox, Safari, Opera and Chrome. Take a look at all the border properties of CSS3 and how all the browsers handle all the values. Everything you could ever want to know about CSS3 border properties, values and browser support, in grid format. CSS3 Border Properties »
There are 8 attributes controlling background images, including those added in CSS3. This blog post goes over all the CSS2.1 and CSS3 background properties, values and browser support, how to target those properties via the DOM, with information on bugs you may find when implementing background properties
Developers have been dividing their code, creating 3 <ul>s and floating each left, followed by a clear, to better use screen real estate. CSS3 solves this issue with the 'Multi-column Layout Module'. We can now maximize the use of a large screen real-estate, by including limited-width columns of text placed side by side. Well, at least we can in non-IE browsers. Here is a grid of the CSS3 Multi-column Layout Module, all the properties, values and current browser support.
Up to now, web developers were limited in what typography they could use on a website to what the client had installed in their environments. Now that we have finally convinced designers to not include any fonts outside of georgia, helvetica, arial, times roman, and a handful of others because of the awfulness of text images, @font-face allows us to retrain designers to use unique fonts, only if they have the legal right to post those fonts on the web. This article explains how to do it, and what features are supported in the various browsers.
A list of all of the CSS3 Selectors (which includes all the CSS1 and CSS2.1 selectors), with a grid of every modern browser, and the support for each browser of each selector. Included at the bottom is a commentary on each browser and their quirks in handling a selector, if there are any.