The undiscovered iPhone killer. The UI is simpler than the iPhone. Offers XBOX Live service, to be updated to become more comprehensive in the Fall "Mango" update. Offers Zune, which can enable unlimited downloading and streaming on the go via a $150 annual Zune Pass option. Zune Pass also enables the user to own 120 songs that are not restricted to being played by Zune capable devices (i.e. Macs, other MP3 players). Offers Microsoft Office and multiple synchronization services, via Sharepoint or Skydrive. Pioneered many ease of use functions that will now be incorporated into Apple's new iPhone 5. Additionally has many phone models than the iPhone, but are all built on the same phone hardware base (thereby providing different form factors for the exact same phone).
Will be adding user friendly and practical features in the Fall "Mango" update, most notably being Local Scout (delivers an array of local features and places to the user), Image/Music search (On-demand search of visual/audio feedback via Bing/Zune/3rd Party Applications), Email integration (Can congregate email accounts together, supports email "conversation" format), and will also be adding more third party support for "Live Tile" homescreen interfaces.
Has a notable lack of advertising, and has never flaunted its own ego like a jackass. Android or iOS have clearly done so on national television.
I'm loving my Windows Phone 7 device, but seriously Microsoft, where's the product placement?