Vanquish is the first that comes to mind.
It's a solid TPS that enjoys taking the piss out of 'western sci-fi'.
-It also reminds me of 'Zone of the Enders' in terms of graphical feel.
Earth Defense Force: Insect Armageddon is another GREAT game.
It's a glorious Japanese B-Movie homage with solid TPS action.
-Though it CAN get a bit...repetitive...in long bursts.
Front Mission: Evolved is a solid TPS with, well, big robots.
It's not as good as the main series (FM4 will forever be my love) but it's an overlooked, solid C to a C+, of a game.
-It IS kind of short, depending on which difficulty you plan.
Killzone 2/3 are, again, solid FPS for the PS3 and both games are LOADS better then the first one.
Red Faction: Guerrilla is basically GTA on Mars, but with more 'destroy pretty much EVERYTHING'.
AVOID that 'Armageddon' game as it sucks, so bad.
WarHammer 40k: Space Marine is a GREAT game, just some dumb fun.
It CAN be challenging, even 'cheap', at times, but I love it.
-If you had/have PSN+ it was free, so, yay!