This has been annoying me since I upgraded to Outlook 2007. Sometimes I need to cancel a meeting without sending a cancellation to those invited. For example, when my boss stops me in the hall and says, "I deleted our 1:1 from my calendar for next week because I'm on vacation" -- when that happens, I just want to delete the occurrence from my calendar as well without sending her unnecessary email.
Will Outlook let me do that? Not. The choices are (1) Send cancellation, or (2) don't cancel. I've looked and can't find a way to do what I want, so today I tried a work-around: I cancelled the meeting occurrence, and then in the resulting email form, I deleted the To recipients and entered my own email alias, then sent it.
Result? Meeting removed from my calendar (which is what I wanted). I never received the cancellation email that I sent to myself, so I didn't even have to delete it (which I'd rather do than send it to others who didn't need the notification).
My opinion is that it wasn't a good idea to remove the old option of "cancel without sending cancellation", but at least there's a way to get around it. So I thought I'd share in case someone else was struggling with the same issue.