On the MSDN you can find a recording of the PDC demo where we showed new CSS editing tools as well as improvements in the client script intellisense

http://www.microsoft.com/emea/msdnshowtime/sessionh.aspx?videoid=318

watch "CSS Editing in Sapphire" where our program manager Brad Milligton demoes CSS tools of the new designer. "Sapphire" is code name of the project which goal is to replace existing HTML designer in the Visual Studio by a new one. 

Another interesting section is one about improvements in the client script intellisense and debugging, including extensive support for Atlas/Ajax, external script files and script libraries.

My team owns both Sapphire project and client script support improvements. So expect more blogging from me about the new editor and designer features in January.