My shortlist for exclusives is
Demon's Souls
inFamous 1 and 2 (or just Festival of Blood)
Katamari Forever
the two Kingdom Hearts HDs if you're into that
Little Big Planet 2
Puppeteer
Ratchet and Clank: A Crack in Time
Siren: Blood Curse
Tokyo Jungle
Yakuza 3-4
Tales of Graces is platform-exclusive in the west.
I'm a huge Tales of Graces fan, though. It was the last Tales game I genuinely liked inside and out, but a lot of people really dislike the story and characters. So if you're into characterization and melodramatic subplots, just wait until the game gets massively cheaper. It's also on PSN in a bundle with another Tales game and it's on sale this week, so if you have some cash, take a look. I don't think the Japanese demo is still on JPSN.
Seconding the Asura's Wrath mention. I thought I'd hate it, but the soundtrack is really sweet and the visuals are amazing. Sucks that the ending is DLC but at the time I felt like it was worth it, and I played it a year out after its release. The English VA in that game is really good.
Uhm... Let's see...
Resonance of Fate is good. You can easily break the game after a while with Hero attacks, but I think the vignette storytelling is decent. ALSO IT'S A FASHION RPG~.
I would've recommended Atelier Ayesha because a lot of people who've played that series in and out say it's the best one, but 1) I can't vouch for it myself, since I haven't had the time to play the games past Atelier Totori, and 2) It probably has a better PLUS version on Vita.
Metal Gear Rising: Revengeance is an excellent, but flawed, game. I gave it my soundtrack of the year when it came out and waxed poetic about it for paragraphs and paragraphs. Once you have parrying down, the world is yours for the taking. It's one of the most mechanically-satisfying games I've played, and the soundtrack truly enhances the experience. However, if you have a rig that can run it, I'd say go with the PC version.
The Uncharted games are pretty decent, though I generally don't like shooters so I'm not sure what I can say to sell them. I haven't played 3 myself because I was told that I'd probably hide under my covers while playing it since it has enemies that I'd probably be afraid of, but 2 and 1 were okay. Sunblade likes 3 the most because the melee is a lot better, but much of the game doesn't seem to make sense at all. It has a lot of neat townscapes, though--much of its soundtrack is pretty nice. 2 is okay. It has a neat visual style and some of the level ideas are cool and well-executed, but the final parts of the game are so bad. Especially the final boss. 1 is all right. I like that it has a lot of platforming and puzzle-solving since that's what I went into the Uncharted games for, but I don't care for the shooting much since some areas get horribly reused, especially the ending. And a trend I'd noticed about the Uncharted games was that they come apart at the seams at the end. They lose their carefully-constructed structure, they end up being repetitive, and the last few chapters end up being so exhausting because they just keep
going. But most people seem to like them a lot so maybe you might too.
Trinity: Souls of Zill O'll is only six bucks on PSN right now, I think. It's by Omega Force so you'll probably know what to expect. It's not a complete Musou game, though. The narrative's all right albeit fairly traditional (about a half-elf who wants to avenge his father and is destined to kill the emperor), and it's essentially a loot game where you can set up combos and group attacks, but it's a nice way to see how an RPG musou would be like: lots of loot, RPG elements and enemies can come at you in droves if they're smaller / cannon fodder, but it's pretty well-balanced even if the maps are a bit meandering and the game's a tad repetitive. I liked it a lot, just because the characters are neat and the story progression was interesting for an RPG by Omega-Force. I'd like to see more games like that out of them.
3D Dot Game Heroes is okay. Decent soundtrack, neat look, and can be difficult depending on what you do/how you customize. It
can be somewhat slow in terms of progression if you decide to explore more than progress quickly, but exploration is encouraged since it's essentially a riff on The Legend of Zelda and Dragon Quest. It also has a Spelunker mode where you can die in one hit.
I don't even think it'd hurt to try out the FF13 trilogy even once since the games are really cheap and since it's been years out after people played them that approaching them with a clearer mindset would result in a more balanced view of the games. I don't think they're terrible (they're actually pretty middling!), but all three games have their shares of awkward structure balanced with good presentation and great soundtracks. I think they're worth playing just once just to see how you'd feel about them in terms of where the series is at the present time and because some of the systems they have
are okay. Good advice I usually have is to never use auto-battle since it drags battles on all the time (it chooses the slowest spell animation in the event that the enemy does not have a weakness which is the wrong way to approach it), so I'd rather choose my own options. I've timed everyone's animations so I know what generally works and what doesn't, and auto-battle, 8 times out of 10, does not choose the fastest or most important option since its options are generally set to a default list.
A special note about Nier: I don't think the game is for everyone. In fact, I kinda hated it when I first started playing it because the combat was
so so so shallow, the side quests' structure sucked, and the drop rate sucked. But after a while with it, I started to realize that the game should truly be played for its narrative structure, its characters, and its dialogue. It wasn't until I hit one particular point in the game that I realized that I should just play it for the narrative than for its systems, and it benefitted my outlook of the game. By the end, I really enjoyed it even if the combat was shallow. It has a lot of homages to other games and other genres of games and that's one of the biggest things that I appreciated about the game. I love when games do that without being so overt about it. Nier was a fun time, but if you're not digging the story, then I don't know if it's for you.
I was going to mention Alpha Protocol, Red Seeds Profile/Deadly Premonition, Dragon's Dogma, El Shaddai, Guacamelee!, Hard Corps: Uprising, Mega Man 9/10, Pac-Man Championship DX, Rayman Origins, Saints Row: The Third, King of Fighters XIII, etc. but they're multiplatform anyhow. If you can grab any on PC, you're probably better off doing it.
There are probably plenty of games I'm forgetting about so I'd have to go through my shelves again, but don't forget that you can play PS1 and PS2 games on the PS3 via PSN classics if you'd like. If I remember anything, I'll post again. I've probably played 85%-90% of the RPGs on the system, including Japanese-only ones so if you have a question about one, ask any time.
In fact, you know what? Play Sheepy Dawgs