Metal Gear Solid 4: Guns of the Patriots – This is the latest game of the Metal Gear franchise, with the main character Solid Snake rapidly aging and near death. MGS4 has been said by Gamespot to be technically flawless. A unique feature of the gameplay is that Snake’s combat abilities can be affected by his mental state during battle, which is affected in turn by battlefield conditions and health.

Uncharted: Drake’s Fortune – This is an adventure game along the lines of the Prince of Persia series with FPS elements added. It centers on an explorer who is the descendant of the pirate Francis Drake. A notable gameplay element is the lack of any on-screen health indicator; instead, the screen display desaturates. The game was known for having production values that nearly reached blockbuster film levels.

Valkyria Chronicles – Valkyria Chronicles is a tactical role-paying-game by Sega. It is known for its lush watercolor-like graphics and the tighter control of strategy. The player can control the individual actions of characters in real-time as they move into attack positions. The setting of the game is an alternate history of 1930s Europe.

Heavenly Sword – One of the first best-selling games on the PS3. This game was innovative in its use of many enemy models on screen at one time, allowing the main character Nariko to engage hundreds of fighters at once. The game made heavy use of cinematic gameplay, also called interactive cutscenes and had a sweeping, epic storyline.

Ratchet and Clank Future: Tools of Destruction – The newest Ratchet and Clank game showed what the Playstation 3 hardware can do. It’s one of the first games, along with Heavenly Sword, to make extensive use of the SIXAXIS motion-sensitive controller to direct projectiles. It is widely considered to be one of the best exclusive PS3 games thus far, and a solid entry to its own series.

Hungry for more? Check out the Wikipedia page Playstation 3 Only Games.