I'm still having a hard time saying "Exchange 2007", because "Exchange 12" just seems to roll off the tongue much easier. Oh well, I'll eventually get used to it.
Anyway, after seeing a demo of Exchange 2007 at the local Exchange User Group meeting (http://www.mneug.org), I'm really looking forward to the Beta 2 release of this product, and obviously the release date sometime in 2007. To summarize some of what I'm excited about:
CCR and LCR (clustering technologies) - CCR (Cluster Continuous Replication) is going to be great for distributed environments or DR scenarios. LCR (Local Continuous Relication) looks good, too. :) More on these when I dig up some good information.
OWA - Near-Outlook level functionality. Every release seems to blur the line further between client and web-based e-mail interactivity. Granted, OWA in Exchange 5.5 was, shall we say, primitive, it still allowed remote access to e-mail without getting into the network (ideally).
Unified Messaging - It was awesome to see the Unified Messaging in action. With Speech Server integrated on the back-end, you can now interact with your mailbox on the phone. And, if you check your mail on a kiosk, or a workstation somewhere you don't want everyone within earshot to hear your voicemail, you can send the voicemail message off to any phone number - your cell, a nearby desk phone, whatever. More accessibility = more ways to stay connected! Wait, is that a good thing? ;)
And, if I may do a little advertisement - http://www.msexchangeteam.com - The Exchange team blog. A great resource, to say the least.