>This mobile prospect needs a fairly simple C#/SQL Server data collection app to run on a mobile device.
>A good keying area is required (users have large fingers!.)
>Occasional web access is required upload/download data.
>What are the best device/platform choices?

A tablet will give the best on-screen keyboard.

Things like a toughbook give real keyboards that are fairly easy to use.. http://www.panasonic.com/business/toughbook/ultra-mobile-rugged-toughbook-u1-ultra.asp

Do you need a bar code or RFID reader or anything built-in?