When we started planning our wedding, Mr. Bruschetta and I set up a joint email account. We hadn't previously shared an email address, nor did we have any combined finances (and still don't).
Thanks to Gmail, we've been able to stay organized (for the most part) throughout the planning process. We've diligently labeled (and, when appropriate, archived) email conversations, created Google Docs to track vendor research and guest mailing addresses and synched our calendars so one knows when the other is available.
We each continue to maintain our own email accounts, and use these individual mailboxes independently and regularly. We have our own passwords, and maintain a level of privacy that, despite our very close relationship, I really value.
I haven't given much thought to what we'll do with our joint email account -- firstname.lastname@example.org -- after the wedding. Most likely, we'll forward messages to another joint account I created -- email@example.com -- so we can still take advantage of the joint calendar function, and keep in touch with mutual friends more easily.
So...do you we-mail? How have you organized your contacts and conversations with vendors?