Email and Calendar
Droid comes with some nice ready-to-use applications, and you can find more in the Android Market place, though you will have to set-up a Google account first. The first thing I did was set-up email. Setting up Gmail was simple. I just entered my username/password and that's it. The Gmail client treats labels like IMAP folders, so I modified which email gets synced by altering the download schedule on each label. I also have an email account hosted on Google Apps, so I set-up multiple accounts.
Setting up Exchange is just as easy. If your company uses Outlook Web Access, it's a simple matter of adding your user account and password, then setting your email server address. Less than five minutes and I had email, calendar and contacts synced. Since all of the traffic travels over SSL, there are no worries about snooping. The calendar events are separate programs and unfortunately, there is no way to sync tasks and notes with the default applications. You will need an app for that.
Beyond basic email reading and replying, forget trying to download attachments. While reading PDFs from a website is easy, downloading the attachment using the outlook client simply failed and offered no indication as to why. That puts the kibosh on activity like reading documents or spread sheets. The G-mail client will open attachments, but in read-only mode with the installed software that comes with the Droid. If you want to edit Microsoft Office documents, you will have to purchase software to do that. One option to open attachments is to forward your documents to a G-mail account and download them that way, but that's an extra step. Sending attachments, however, is not a problem.
The calendaring works a little better once you see it in action but Outlook users will be initially confused because they are used to accepting calendar events in email, not in the calendar. On Android, the email, calendar and contact applications are all separate. This is by design. When you receive a calendar invitation in email, there is no attachment and there is no way to accept. Once you read the email, the invitation ends up in the calendar application. If you hold your finger over the event in the calendar, you get a pop-up menu asking if you want to accept, decline or set as tentative. Select an option, and the event is set.