The debugging team has just released the Debugging Tools for Windows version 6.3.17. There are several new improvements in this release, the most obvious of which is the new UI enhancements which allows you to dock windows, window tabs, and tear window off. A more complete changelist is also on their website.
I'm a big fan of the new UI. I recommend setting up your default workspace with the windows setup the way you like them, so that all other projects inherit from them. In my default workspace, I setup the command window, disassembly, and source code in a big window, in the top left of the WinDbg screen. Registers and scratch pad are docked together in a thin column along the left side of this large window. The bottom portion of my screen is split in half. On the left goes process and threads and the watch window. The bottom right gets calls and locals.
If you're at all a fan of WinDBG I recommend grabbing this update.