I noticed that Microsoft a running a competition where you tell them what app you'd like created for Windows Phone 7. If you win then they'll build your app and also give you a new Windows Phone 7 handset when they come up. Runner up prizes of Zune HDs.

Details here:
http://www.brickfish.com/Lifestyles/ineedthisapp?tab=entries

Out of those I've seen, these two stood out for me:
- Windows Mobile Remote Guide with Record - For Win 7 Media Center
- Windows Live Writer for Windows Phone

I'm curious what app ideas interest others or if any Geekzoners are planning to enter or have entered...?