Enter a URL, preview it on a few different "devices".

Hover on text, see the font being used. From Chengyin Liu.

Matt Wiebe's very useful bookmarklet for testing type now has support for custom Font Family lists, including web fonts.

Tool for auto-organizing CSS files.

Nicholas Zambetti: "LiveView is a specialized remote screen viewing application intended as a tool to help designers create graphics for mobile applications, it has also proven to be useful for creating quick and dirty simulations, demos, and experience prototypes."