In Outlook 2003's calendar, appointments and meetings marked as "Free", "Tentative", "Busy", and "Out of Office" all automatically appeared differently on the calendar view to make it easy to visually distinguish them. Outlook 2007 offers the same "Show time as" options, but does not automatically visually distinguish these statuses by default.
I wanted this feature back in Outlook 2007, because I use my calendar not only to block out time for meeting and appointments which I mark as "Busy", but also as reminders for things I'd like to do if convenient, which I mark as "Free". Items I mark as "Free" are things like "Read the corporate newsletter", "Drink water", etc.
One way to visually distinguish meetings and appointments in Outlook 2007 is to manually assign each meeting and appointment a category which is associated with a color. This is what I did at first, but thought there must be a better way.