Well, I can give you as much information as I know about which pins are rare. In terms of magic pins, the rarest is, of course, inferno, followed by snowman and bat magics. Of the Tomorrowland pins, the orange Tomorrowland 8/9 pin is the rarest. The lion is the rarest Jungle Cruise pin. Apparently, Madame Leota is the rarest Haunted Mansion pin. The third Everest pin is the rarest in that set. I'm assuming the Grand Californian is the rarest hotel pin, but I'm not positive. The 1963 Tiki Opens pin is the rarest Tiki pin, the first pirate pin is the rarest of that set, the surfing pin is the rarest waterpark pin, the Churro pin is the rarest food pin, and the new Eye pin is the rarest Inner-Space pin. I think all of the Hong Kong pins are about equally as rare.
All other pins in each set have about the same level of rarity.
I hope that made enough sense. For pictures of these pins, check out the pin guide in the trades and wishes board.