Games out already
1. infamous
2. killzone 2
3. resistance 1 and 2
4. littlebigplanet
5. uncharted 1

Upcoming games
1. uncharted 2
2. ratchet and clank a crack in time
3. heavy rain
4. gran turismo 5
5. god of war 3

Resistance 2,Infamous and Fat princess are some of the gems.

Valkyria Chronicles
Folklore
Disgaea 3

I'd throw Warhawk, Killzone 2, and Resistance 2 for the shooter category with KZ2 being my prime recommendation.

Little Big Planet, A MUST! greatest game Ever period. no next gen game compares to this great game. Also a plus side is that main DLC (downloadable content) is free. Other DLC is not free but you can still play levels that use them! without downloading the DLC you just can't use them in levels you make without buying the DLC. Customized characters and always new levels to play on.

Warhawk greatest 3rd person shooter. I've wasted so many hours playing this game with friends. A few good features splitscreen online which not many games have anymore.

Rather than mindlessly posting a list of every quality PS3 exclusive, I am actually going to provide a reason to play the games I recommend. 

First, considering that you enjoy shooters, I recommend Resistance 2. This game offers both an exceptional single-player and multiplayer experience. The campaign has an interesting, epic story. Seeing the invasion and destruction of both San Fransisco and Chicago was amazing. Traversing a rural town in Idaho that has been overrun by the Chimera is chilling. The MP has a fun eight-player co-op mode that allows you to explore the story from a different perspective. I will not reveal any details, but it is enjoyable. The MP also has fun competitive modes. The battles are frantic, and the weaponry is both diverse and creative. 

Second, I recommend Warhawk. Granted, I have not played the game recently and am therefore uncertain if there are enough players on PSN to justify this purchase. If there are enough players, this game is worth purchasing. The action is frantic, and the mixture of ground and aerial warfare is excellent. My brother and I had copious fun playing this game. 

I should note that I have not played MGS 4: GotP, Valkyria Chronicles, or certain other top PS3 exclusives. Nevertheless, based on the exclusives I have played, these are the two that I recommend. 

i want games that are high on demand.

don't miss Fat Princess, inFamous, Valkyrie Chronicles, and MGS4

As you would expect, my list is comprehensive:

Valkyria Chronicles
Folklore
Flower(PSN)
Wipeout HD(PSN)
Disgaea 3
LBP
Resistance 2
Uncharted
Killzone 2
MGS4
Siren(PSN)
Ninja Gaiden Sigma
Infamous
Heavenly Sword
Final Fantasy VII(PSN)
Metal Gear Solid(PSN)

Skip the rest. Including Warhawk, any racing DEMOS, Motostorm, and Fat Princess. Meh. You won't be sorry with the games I've mentioned.

As for LBP, rental is best.

If I had to trade Galaxy, Twilight Princess, Bioshock, Modern Warfare, MGS4, Valkyria, Vesperia, or Fallout MF'n 3 for LBP, I'd literally shit myself and die with the shit still in my clothes.

LBP is good, but to say nothing compares to it this gen, makes me nauseated.

What have you never been on the Sony discussion boards? They are talking about all their favorite games all the time. Go there. Use your brain. It's not hard.