This is a discussion on What's your rarest plat? within the General PS3 Discussion forum, part of the Everything PlayStation; My rarest would be MLB 11 the show earned by 16 (4.83%) of 331 but since that's not that many ...
my rarest plats are: LittleBigPlanet & Dead Nation - both have been earned by about 15% of owners each
Uncharted: Drake's Fortune | Bioshock | Mini Ninjas | Sly Cooper and the Thievius Raccoonus | Sly 2: Band of Thieves | LittleBigPlanet | Trine Terminator: Salvation | Assassin's Creed II | Uncharted 2: Among Thieves | Dead Nation | Resident Evil 5 | Batman: Arkham Asylum
Sly 3: Honor Among Thieves | Jak and Daxter: The Precursor Legacy | Trine 2 | Borderlands | Singularity | Dead Space | Sleeping Dogs