Owning a Windows Mobile mobile, is like a torture. As an owner of a Samsung i600 (Known in the USA as AT&T Blackjack - Windows Mobile Standard 6.0 - no touchscreen) and of a Sharp WS003 (Windows Mobile Professional 5.0 - with touchscreen), i can easily affirm that both standard and professional devices are NOT optimized for real-life usage. Very long loading times, useless on-screen-keyboard (unless you have the precision of a neurological surgeon), and "broken" software (I mean: it is not polished and refined). This is mainly because Microsoft gives to manufacturers a "raw" operating system, and they have to add, polish and refine functionalities at their own expenses. Photo management? You do it by yourself. MMS? Do it. Wi-fi and Bluetooth stack? We give you a basic one, if you want you can enhance it by yourself. Accelerometer, GPS and so on? They will be invisible to the default system, you have to write your own drivers. 
So, many manufacturers, has sold Microsoft "plain" operating system, like my old MiTAC Mio 8390, an awful mobile with a lot of bugs; while others, like Samsung, has splurged on third-party licences, to make look Windows Mobile more refined.
Nowadays, with the iPhone, Android and the very promising Palm Pre, the smartphone compatition is becoming very interesting, so Microsoft has finally decided to innovate his Windows Mobile, virtually unchanged since 1999. 
On the Mary Jo Foley's blog, there are the supposedly leaked specs of the new Windows Mobile 7 platform, codenamed "Pink phone". Those are the minimum requirements that every device must have, codenamed "Windows Mobile 7 chassis 1":
Core requirements:
Processor: ARM v6+, L2 Cache, VFP, Open GL ES 2.0 graphics HW (QCOM 8k, Nvidia AP15/16* and TI 3430 all meet spec)
Memory: 256MB+ DRAM, 1G+ Flash (at least 512MB fast flash – 5MB/s unbuffered read @4K block size)
Display: WVGA (800×480) or FWVGA (854×480) 3.5†or greater diagonal
Touch: Multi-touch required
Battery: Sufficient to meet Days of Use LTK requirements.
Controls: Start, Back, Send and End are required (soft controls allowed as long as they are always present).
Peripherals:
Camera: 3MP+, flash optional, 2nd camera optional (VGA resolution sufficient)
GPS: aGPS required
Sensors required: Light Sensor, Compass (3 axis, 5 degrees, 100 Hz sample rate), Accelerometer (3 axis, 2mg resolution, 100 Hz sample rate)
USB: High speed required, 20 MB/s transfer rate.
BlueTooth: BT2.1 required, must run MSFT BT stack, CSR BlueCore6 or later recommended.
Wi-Fi: 802.11B/G required, must run MSFT Native Wi-Fi stack, Atheros 6002 or Broadcomm 4325 recommended.
Connectors: Micro USB and 3.5mm Audio required.
Options:
FM tuner: If tuner HW is present it will be detected and supported by the Media application.
Haptics
SD Card (Micro SD recommended)
DPAD, qwerty or 12/20 key keyboards all optional