For Xbox, I can't recommend
Lost Odyssey and
Tales of Vesperia enough - two very solid titles

I put roughly 150 hours into Vesperia through a couple playthroughs.
Eternal Sonata is worth a look also.
Skyrim is also a lot of fun, but I prefer that on PC because of the modding community.
The PS3 has a great selection of RPGs as well. Ni no Kuni and Tales of Graces F are a blast

Not to mention Tales of Xillia coming out this year. I would wait until after the Sony Feb 20th event though as others have mentioned - they may price drop the PS3.
I enjoyed
Nier quite a bit also! It's not exactly a full-blown RPG, but it has similarities - more like an Action RPG. If you try it, be sure to give it more than just the intro portion. It's one of those games that really grows on you and the story isn't half bad either - one of my favorite things about it was you can do a 2nd (and 3rd / 4th for a different ending) playthrough and it translates what the enemies are saying, so you learn their side of the struggle
.
Divinity II: Dragon Knight Saga is another good title

It has a budget-game vibe to it, but it's really enjoyable. It has been described as a 'poor man's Skyrim' but I think it's a lot better than that. It's a very long game, has a huge world to explore, AND you can morph into a dragon that has its own set of attacks and fly around the world.
There's also a Space RPG called
Darkstar One: Broken Alliance that I enjoyed. It has escort missions, trading routes, lots of pew pew combat, you can upgrade your ship (Weapons vs. Armor vs. something else I can't remember.. lol) and it changes the appearance of your ship which is nifty. I think it's a medium-length game, I spent.... 40? hours in it getting 100%. The story is a bit cliche, but still enjoyable.
If your into Co-op at all, Tales of Vesperia has co-op combat for up to 4 people which is a blast
Hunted Demon's Forge is more of a Gears of War Style shooter, but it does have a few RPG elements such as upgrading spells / skills. Lots of fun in co-op!