[TurboFool]

To re-write it in case mine makes any more sense:

You have what's assumed to be virtually unlimited POP/IMAP accounts. I know I have three, and I'm pretty sure you can have a lot more than that.

You can have only one Exchange account. Whatever you sync with Exchange wirelessly, though, cannot be synced with your computer via ActiveSync. So if you set it to sync your mail, you can't also sync it with your desktop. As far as I was aware this held true with calendar, contacts, etc. But if you just set up your home Outlook to use RPC over HTTP then it'll sync the same information anyway, making the phone unnecessary for that task.