Rightclick is part of OD correct? If it is...
I have always wanted the ability to edit OTHER rightclick menus and not just the desktop one. I have some nice ideas on how to go about this to make it smooth and simple.
Also have more cross program interaction. WB on Vista already skins "extra" parts of the system by using other sections of the windowblind skin. OB2 can copy your taskbar image and use it for its own bars. Stuff like that for widgets or object dock would be pretty cool.
A program that does for the Task Manager what EFD (Enhanced File Dialog?) did for the save/open menus. Just have it more advanced. Like the ability to "hide" programs that the OS always runs (like Vista did), rename programs so they aren't like sass.exe etc, add custom comments to programs. That sorta thing.
Sort of like above, but something like that for the add/remove programs menu would be nice too. The ability to hide/show programs, rename them, add comments, last used/opened/edited, etc. Just more advanced menus that give more information to the user

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A registry URL bar would be wicked... so it shows the keys location (and you could type ones in also). When getting help many people tell me to "locate HKCU\Software\Microsoft\Windows\etc etc etc". Copy/pasting that location into a bar would be cool

. Guess thats more of a tweak that could be put into an existing program than a whole new program lol.
Thats really all I can think of right now