Now you can run Android app in Windows desktop! Well, thanks to BlueStacks' virtualization magic, you'll be able to run Android apps alongside Windows apps and switch between them just as you would between different Windows apps.
Furthermore, BlueStacks will make use of your Windows drivers -- which will allow you to print stuff from within Android apps, or even use Skype for Android with full audio and camera support. Well for now, the Android Market won't be available inside BlueStacks, but you'll be able to access Amazon Appstore.
The idea, suppose to be is to give you the ability to run Android apps on your Windows PC without having to have an Android smartphone or tablet. Exactly what those apps would be is my question: what's available on Android that you can't a Windows equivalent?
More Info: BlueStack