I have just finished hacking my first Windows Live setup - I have accelerated video drivers, audio, I can see movies using ffdshow, Mozilla Firefox, Total Commander, Norton Ghost, DirectX.
I have used BartPE and Sherpya WinPe Stuff.
The hard part was getting NVidia drivers to work and then the sound drivers. Now I can say that I have a better undestanding of manual loading of drivers on Windows XP :)
Pretty nice stuff, but you have to work to get it working...