Consistent set of Hardware capabilities is now defined by Microsoft for the Windows Phone 7 devices. And Microsoft is very proactive in defining these hardware specifications unlike earlier for Windows Mobiles where it was flexible. It has set kind of standards such as, the front of the phone will have a multitouch display with 3 buttons generally positioned below the display, namely – Back, Start and Search. So I think the Start button of Windows Phones will be as famous as that of the Windows OS.
During the MIX10 , Joe Belfiore in this video Changing our Game – an Introduction to Windows Phone 7 Series has shown the required hardware specifications for the Windows Phone 7 series devices.
Click to enlarge
Screenshot taken from video - Changing our Game – an Introduction to Windows Phone 7 Series -Joe Belfiore
As you cans see from the above pic , all Windows Phone 7 devices will have -
Symmetric multi-touch of Capacitive type with at least 4 or more contact points.
Sensors – A GPS, Accelerometer, Compass and rest of sensors.
Camera with 5 megapixel or more , flash and a camera button
Multimedia – Codec acceleration
Memory – 256 MB RAM or more , 8 GB Flash or more
GPU –DirectX 9 acceleration
CPU – ARMv7 Cortex/Scorpion or better
3 Hardware buttons – Back, Start, Search is a must and other buttons like buttons for Volume and Power.
These devices will come in 2 screen sizes – 800 X 480 WVGA and later with 480 X 320 HVGA screen size devices.
Slide courtesy - Overview of the Windows Phone 7 Series Application Platform - Charlie Kindel
Hardware Specs for Windows Phone 7 Series