I am also looking for the "Private" option. I like to have one calendar and don't necessarily think my coworkers care when my son is out of school or when I have a hair appt scheduled, etc. I have always been able to use the Blackberry to do this and it doesn't seem possible with the Moto Droid at this point (without paying for touchdown).
As far as a corporate phone... the Droid is NOT. I love it for playing, but it just isn't practical for a corporate exchange environment.
I am pretty sad, because I am told "Droid Does". When I have to now maintain 2 calendars, I can't really buy that line.