Stealing the idea from Twesterm:

Uncharted -- very good refreshment of Tomb Raider idea with a bit more shooting.

LBP -- interesting unusual platformer , altrough all the comunity stuff is way too exagerrated, real fun is in creators levels when played with family or friends locally.

Killzone 2 -- generic shooter title

Wipeout HD -- probably best existing arcade racer, requires mad skills and tons of time but satisfaction from betting some of the challanges there is great. Also best ever value for download only game ever.

Flower -- unusual experience, worth checking as one of more unique "games" in existence

MGS4 -- this is game i'd love to see how someone plays it all but i feel absolutely no need to play it on my own

Resistance: Fall of Man -- classic FPS, usually can be found dirt cheap so worth checking
Resistsance 2 -- I only checked multi , which was good (becouse it reminded me of counter strike), imho R1&R2 can be skipped without losing much.

Ratchet and Clank -- I hate 3D platformers

Eye of Judgment -- i find it pointless, they could just as well made cards fully virtual. If i wanted CCG on screen I'd go for magic online.

Motorstorm -- boring when compared to Wipeout

Valkyria Chronicles -- holy grail of SRPG lovers, if you don't like genre you probably won't understand why people love it so much

Folklore -- Try demo. It's extremly interesting and great game but it might be not your cup of tea.

Heavenly Sword -- Gow clone, but much more enjoyable imho. Demo is pretty weak compared to full. Also it's very short so get it only if you can buy

HAZE, LAIR, Afrika, Cross Edge, and Genji. Almot forgot Mobile Suit Gundam... thats a must!

Easy folklore that game is great, and almost all of ps3 owner do not even know that game exists, that game is great with a very exellent final. about 90 percent of ps3 owners hasn't play it.

Eh, I think a lot of people have played the demo but most didn't go much further than that because it wasn't that great of a game.  It's not it's a bad game, it's just nothing special and that's why it usually isn't talked about.

It's not good enough for people to hype beyond belief and it's not bad enough for people to constantly mock.  It's just there.  I would say try the demo first.

selnor how can you even compare the X360 to PS3 to each other and claim this library is better than that when you aren't familiar with the PS3 lineup?

It's kinda strange that you haven't kept track of the PS3 exclusives better than this, so that you feel the need to ask forum members of tips.
(starcraft did this too when he bought a PS3)

I think the best games on the console have already been mentioned. Also, Flower and Flow are 2 games that are slightly more obscure for download and actually make use of the Sixaxis. Might be worth checking out for something a bit more unique.

I'm guessing you'll have most multilats on 360?

Must haves:

Uncharted 1 & 2 (based off the beta)
GT5: Prologue (or you could just wait for GT5 I suppose, but download the GT:HD concept in the meantime)
Killzone 2
MGS4 (if you're an MGS fan, otherwise might be a bit too much story-wise)
Resistance 1 & 2 (The co-op in 2 is particularly good)
Heavenly Sword (short but I think its cheap now, not worth a full price-tag)

Recommended:

LBP might be worth getting, not my cup of tea but everyone else seems to enjoy, lol.
Demon Souls is worth checking out by all accounts as well.
inFamous

folklore
best ps3 game

I'm mainly asking about obscure titles. I have played quite extensively KZ2, Uncharted, MGS4, Lair and GT5P. The rest I haven't played much if any. No better way than to ask those that have.

Love the comments guys. Keep em coming.

For Disk games i'd really reccomend you get Valkyria Chronicles, as well as Demon Souls and LittleBigPlanet.

For PSN games i reccomend you get Pixeljunk Monsters and Fat Princess.

Wow i have 666 posts now <___<

I'd disagree. The game was brilliant.

One of the few games that uses the Sixaxis well and it also has a very deep, involving story.