Well it appears the PDC build is indeed 5219. I will throw up some screenshots later, mirror the ones on uxevolutions, anyway here’s what’s new in this build:

Contrary to popular belief the REAL build tag of the PDC build is Build 5219 (winmain_idx02.050830-2010)

* Sidebar is back (Not in the PDC build)
* Outlook express how has an RSS reader integrated
* Outlook express showing more of the visual overhaul
* glass taskbar
* previews of applications on taskbar
* 3D task switcher and 3D Carosel type task switcher
* Picture editor
* Photo album
* Movie Maker 3 with DVD authoring
* .NET 2.0 framework
* System restore wizards
* System backup wizards
* Software version of windows update (now does updates like OSX)
* Pictures have a border around them in thumbnail view
* Popup extended preview on items in explorer (biger thumbs)
* Expanded driver support
* Performance fixes
* Bigger LDDM Driver support
* IE’s CSS support has been expanded since beta 1
* PNG support for Icons (icons are all in PNG format now in a packadge called .ICO)
* Windows Media Player 11 (not included yet, but bits and pieces of it are in this build)
* Major changes to UAP and it’s functionality (works better, less prompting for admin passwords where they shouldn’t be needed, better settings and control over UAP)
* Taskbar tray icons are now being formatted in 32×32 icons. for larger res monitors if you make your taskbar bigger it will increase the scaleing of the icon also.
* Taskbar tray icons are mainly black and white now. White icon with a black shaddow (similar to OSX’s black icons)