I haven't actually used Outlook 12, but I just read a short list of Omar Shahine's favorite features. I look forward to the new features (there is also a document auto-preview that looks cool but I really look forward to figuring out how it's breaking my system).
I find the color categories feature strangely familiar from gmail...maybe they'll incorporate that feature into Windows Live and really copy Gmail. ;-)
In MS's defense, at least they're not too proud to copy features (or buy companies) when they're out-innovated.