If there is one important feature that is missing in Windows Phone, it has to be a Notification Center. If you have used Windows Phone before, you will realize that once you failed to read the notifications, they will be gone, like forever.
The good people from windowsphonehacker has done something that might solve this problem. As a proof of concept, they had posted a video on how their notification center works.
Here is the video.
In my opinion, Microsoft should have done this long ago. Live tiles are great but having a notification center like the one windowsphonehacker has done, it will be better.
BTW, for the above app to work, it will need a Windows Phone that is developer unlocked.