I have always been puzzled about the "rare"-ness of items. I am under the impression that rare should be equated with limited availability as opposed to popularity, which equates to value. Just a thought.
Now, for those of us who were lucky enough to stumble on the minnie hat on the Tuesday that it was "accidentally" sold for about 30 minutes, that was (at least for me) the most hilarious week in VMK. Not knowing whether it would ever be released again, I was offered the most amazing trades. Of course, for that reason, it has always been my favorite VMK item.
The most difficult hat to get, sans stitch and sparrow, was the purple baseball hat. That quest, for me, was nearly impossible. Not because we didn't know the answers, but the DC monster kept eating us while we tried to get the ghosts needed in mansion. That was back when you were thankful to get through a game of mansion without disconnecting.