I think it very much depends on what you're going to use your iPad for.
Mine is used as part of my profession - so I have the Apple iWorks suite for the iPad
'Pages' - for MS Word files
'Keynote' - for MS PowerPoint files
'Numbers' - for MS Excel files
'Informant HD' - a more comprehensive calendar, project and task managing app
'MailShot' - for allowing me to send emails to Groups of people in the iPad email app (the native app doesn't have that capability)
'PCalc' - fully featured scientific calculator
'PrintCentral' - allows the iPad to print to non-Apple-AirPrint compatible printers
'iDraw' - drawing package for technical drawings.
'Kindle' - for reading a wider range of books than Apple's iBooks store
But, as I said, I think that you'll get very different answers depending on the use to which members are putting their iPads
Tim
Scotland