- Primarily voice, with some data
- Primarily e-mail, with some voice and data
- Primarily data, with some voice and e-mail
RIM's 7200 product, which is only $400, offers PDA functionality, GPRS voice and data and, of course, e-mail. Peter says RIM offers end-to-end security, but I'm not really sure how.
The PalmOne Treo 600 is also quite popular, albeit more expensive. Plus, you can find lots of applications to keep track of your golf handicap--although I think most applications are limited to two digits. The form factor is very nice, and everyone I've spoken to who owns one absolutely loves it.
On the Symbian front, you can look at the Sony/Ericsson P-900 or the Nokia Communicator, which, in my opinion, is a little too big.
For Microsoft, it's a choice between Pocket PC Phone Edition and Microsoft Smartphone. The only Microsoft Smartphone is from Motorola. A number of nice products based on Pocket PC are out there, and you give up nothing compared to a PDA.