Little Big Planet 1 or 2, Motorstorm (any of them), Uncharted 1, 2 and 3, Metal Gear Solid 4, God of war 3, Resistance 1, 2 and 3.

Edit Sorry I keep thinking of more so i keep editing!

Valkyria Chronicles

Heavy Rain and Killzone.

And as a fan of kart racer games like Mario Kart and Crash Team Racing.. Should i get Modnation racer or Little big planet karting?

For you or anyone else that might not be aware, if you wait till Black Friday and Saturday you can get a 250GB console, Uncharted Dual Pack, inFamous Collection and PS Plus trial for $199. http://www.engadget.com/2012/11/16/sony-ps3-ps-vita-bundles-black-friday/

Save your money and go buy Wii U.. its out with alot of great and enjoyable games :|

You don't like RPG games? You can try finding your game here

Plus is worth if you have fast connection and you have a big hdd...Personally I've used it for 3 months and I played great games (Space marines, Red Dead Redemption, Infamous 2 and others small games)...you also get good discounts and early access (as well as plus exclusive).
I suggest you to play: ALL metal gear solid saga (you can buy the HD collection), ALL final fantasy (or at least the best ones [V, VII, VIII, IX, X, X-2, XIII, XII-2]), God Of War and Silent hill (again you can buy HD remake for cheap)...if you have troubles, questions or a buddy to play with, hit me on steam and I can help you/give my psn. Have a nice day

EDIT: LITTLE BIG PLANET 1 AND 2 ARE A MUST HAVE

I really hope you got at least 500GB storage, see... brace yourself, because of PS+ free games my 320HDD is wasted , I ordered a 1TB as I have 27GB to grab in queue
Crysis 2 for free is waiting for you btw

I'm currently using a PS Plus trial and so far it really seams worth the price as I've been able to download the first three Assassins Creed games plus more and play them for free (Although technically not free if I was paying for the service but at the yearly price its a bargain). The only downfalls I can think of are if you have a small hard drive then you cannot download much and if your download speed is slow it will take years.

skate 3 if ur into skateboarding

PS+ is only worth it if you're willing to subscribe every year. But if you are, it makes more than your money's worth, as games nowadays are way too expensive and you get like 3 free games a month minimum. Though they're usually sandboxes/shooters.

[TROLL] Halo 4

Demon Souls/Dark Souls, Way of the Samurai 3(only one i played) if you like fighting games soul calibur and Tekken comes to mind

Disgaea series is also lots of fun if youre into that kind of games ;)

If you want a pretty decent little game that's kept me amused for many a night - Tokyo Jungle.

I do second the notion of the Metal Gear collection. The HD version of 2 and 3 are epic. And if you get the boxed retail version you get Peace Walker..Which in my opinion is probably the best Metal Gear ever made.

The Last of Us is coming out soon. Can't wait :D

"Are there some good games that are only on PSN, like Fat Princess?"
Journey

MGS4, The Last of Us(coming soon), Uncharted

If you're a fan of NIS games, there's always Trinity Universe. If you like games that are moderately hard with relateable characters, try Resonance of Fate.

Well I had an old PS3 as a gift a few days ago and Journey is one of my priorities...

Metal Gear Solid 4: Guns of the Patriots, God of War 3, Collection, and whatever the PSP compilation was, Tokyo Jungle, Valkyria Chronicles.

I feel sorry for you.

i always wanted to try heavy rain myself

PSN+ is only worth it if PS3 is your main platform for gaming. Most people talk about uncharted and other PS3 exclusives, for me those games are good but they are not what define the PS3. Games like disgaea, gundam VS, macross, super robot wars,catherine, etc. shine in that console. Look at the japanese games those are the ones that make PS3 a worthy console to have. unfortunatly there are very few great JRPG, xbox and wii managed to steal the thunder in that genre...