I'll give a detailed answer and list all rpg's released in Usa for PS 3 with information on each of them...

Nov 15th 2006 - Untold Legends: Dark Kingdom - It's an action rpg but the reviews and sales weren't great, it's not popular. It's console exclusive. Don't worry about this game.

Nov 17th 2006 - Marvel: Ultimate Alliance - It got good reviews and sales but people on these forums don't mention it since it's more of an action game. This is out on most platforms. If you like action games, rent this if you want, to check it out.

Mar 20th 2007 - The Elder Scrolls IV: Oblivion - This is a first person rpg using a fantasy style and set in a medieval setting. It's critical and user reviews and sales were extremely high and it's one of the very best rpg's out in this generation. It's also out earlier for PC and Xbox 360. This PS 3 release also includes the Knights of the Nine, the first expansion pack. The game is developed by Bethesda Softworks, who is developing Fallout 3 now, with the same team I believe. I highly recommend this game! The main quest is like 20 hours and the side quests are like 300 hours, yes it's long.

Apr 03rd 2007 - Enchanted Arms - This is a traditional rpg. The reviews and sales weren't great though. It also came out earlier for Xbox 360. Don't worry about this game.

Oct 09th 2007 - Folklore - This is an action rpg, it has a dark style I believe. Reviews were good but I don't know if the sales were. It may be a hidden gem. This is console exclusive. Rent this game to see if you like it.

Oct 16th 2007 - The Elder Scrolls IV: Game of the Year Edition - It's kinda an upgrade of The Elder Scrolls IV: Oblivion. This is a first person rpg using a fantasy style and in a medieval setting. It includes the original Oblivion release, the Knights of the Nine expansion pack, and the Shivering Isles expansion pack. Reviews and sales were high and it's one of the best games for the current generation. It came out a bit earlier for PC and Xbox 360 also. I recommend buying this game!

Nov 20th 2007 - The Elder Scrolls IV: The Shivering Isles - It's the standalone version of the second expansion pack to The Elder Scrolls IV: Oblivion. Read my earlier information on this game. Buy the game, and it was earlier released on PC and Xbox 360.

Aug 26th 2008 - Disgaea 3 - This is a tactical rpg. Expect the reviews and sales to be pretty good. It's console exclusive, and may be the best tactical rpg released this fall. When it comes out rent it and see if you want it.

Nov ?? 2008 - Valkyria Chronicles - This is a tactical rpg from Sega. I don't know a bunch about it, not sure how good it will be but PS 3 fans are happy about it I think. PS 3 gets this game and Disgaea 3 as console exclusive rpg's this fall. I heard that this may be made by the same team as Skies of Arcadia, I wonder if this is true.

Late 2008 - Fallout 3 - This is a first person rpg set in the future in a real world type of setting, although it's a post-apocalyptic setting. The reviews and sales are going to be extremely high for this and it could be the best rpg of the year. It's the same team that made The Elder Scrolls IV: Oblivion. Expect the game to be hundreds of hours long if they try to make it like Oblivion. It's going to be released for PC and Xbox 360 and I don't know if it will be on the same date. I recommend this game.

Spring 2009 - The Last Remnant - This a traditional rpg by Square Enix. I expect it be a great and popular game, although it's going to be released for Xbox 360 this Fall also.

Fall 2009 - White Knight Chronicles - This is an action rpg made by same team of Dark Cloud 1/2 and Rogue Galaxy(Level-5 company). It'll have great reviews and sales I'm sure, look forward to it doing great. It's console exclusive.

Fall 2009 - Final Fantasy XIII - This is a traditional rpg made by Square Enix, from the same team almost as FF X and FF X-2. The reviews and sales are going to be extremely high, and it's sales will surpass Fallout 3 probably, no offense to Fallout 3 fans. This is a "killer app" for Playstation 3 and PS 3's success is partially riding on this game, just like Metal Gear Solid 4 also helped out PS 3. Expect this game to sell over 400k it's first week. Probably the most anticipated rpg since Final Fantasy X!

Fall 2010 - Final Fantasy Versus XIII - This is an action rpg from Square Enix from the same team that made the three released Kingdom Hearts games and Final Fantasy VII: Advent Children. Reviews and sales are going to be extremely high, and the rpg might be the best rpg of all of 2010. It's a "killer app" for PS 3 along with Final Fantasy XIII. People are really excited about this game!

---

That's some info for you, I left out some other rpg's that aren't as huge I think. Check the release schedules on rpgamer.com and rpgfan.com is you want more information. Check out Main Page - Wikipedia, the free encyclopedia for information on some games that you like. Bottom line is that I recommend The Elder Scrolls IV: Game of the Year Edition, although it's also out on PC and Xbox 360. I recommend the PC version since I think you can edit/hack the game right? If you are interested you can rent Folklore and Marvel: Ultimate Alliance. Currently PS 3 is losing to Xbox 360 and Wii as far as rpg's go. But Final Fantasy XIII and Final Fantasy Versus XIII could change everything and PS 3 could wind up on top as far as the system for rpg's, based on the strength of those two games. Although I think overall this is unlikely since Xbox 360 and Wii also have great rpg's.

Best Console Exclusive Rpg's for each three home consoles:
Xbox 360: Blue Dragon, Eternal Sonata, Lost Odyssey
Xbox 360(upcoming): Tales of Vesperia, Infinite Undiscovery, Fable 2, Cry On
Playstation 3: Folklore
Playstation 3(upcoming): Disgaea 3, White Knight Chronicles, Final Fantasy XIII, Final Fantasy Versus XIII
Wii: The Legend of Zelda: Twilight Princess, Super Paper Mario(platformer rpg), Fire Emblem: Radiant Dawn, Final Fantasy Fables: Chocobo's Dungeon
Wii(upcoming): Tales of Symphonia: Dawn of the New World, Next Zelda Game(unannounced but will be coming)

Okay, for the console war in top console exclusive rpg's out so far I think that Wii wins. PS 3 only has Folklore which is good but nothing huge. Wii has Zelda: TP which is a legendary rpg(although you can also consider it an action game but that's not part of this discussion). It also has a few other great rpg's out. Those other three Wii rpg's don't match up to the three best console exclusive Xbox 360 rpg's but with Wii having The Legend of Zelda: Twilight Princess, it wins the rpg console war so far. As far as upcoming console exclusive rpg's go, there's a different situation in this console rpg war. Playstation 3 probably wins the upcoming rpg's war with Final Fantasy XIII and Final Fantasy Versus XIII. They are on the same level as the best Xbox 360(Fable 2) and Wii(Next Zelda Game) have to offer, but PS 3 has both of these games. PS 3's other rpg's coming up match up to the other Xbox 360 and Wii rpg's coming up. But I think that overall PS 3 has the better rpg's coming up from 2008-2010. In this generation it's going to be often that a rpg player has 2-3 consoles, since the rpg's are more spread out than in the last generation when PS 2 dominated.

This post turned into something different from my intention but I felt like giving you information so I hope you enjoyed to read it. And don't forget, I left off many games in this post that are not console exclusive in this format war, like Mass Effect and Fallout 3, they change the scaled also. !!!