I'm going through the documentation on the new .Mac offering and I see that you can now associate your .Mac account with your own personal domain. And the .Mac email is IMAP -- is this new? This might convince me to move away from my slightly unreliable IMAP server.
Further, although you can associate your personal domain with your web page, there does not yet appear to be any way to use it for your e-mail address.
As far as I can tell, there have been no changes to .Mac Mail.