I hate to say it, but the best place for RPGs is probably the PS2. You can get one for 40 bucks, and there are hundreds of top quality titles to choose from. Dragon Quest, Final Fantasy, Kingdom Hearts, and those are only the big ones that I, a strictly Nintendo fan, know about. (I am NOT a fanboy. I play other systems all the time, I just don't personally support them because I do not like the way Sony or Microsoft handle their business)
And don't forget the PS2 is compatible with any PSone game too.
Unfortunately, the quality of older games on the PS3 really puts a damper on buying it and expecting to play old games, especially since backwards compatibility is half the reason to buy a new system these days.
Has someone mentioned Mass Effect on the 360? Because someone needs to mention Mass Effect.
Mass Effect.
Dragon Quest Swords is wicked cool. And don't forget the Gameboy Advance. All the classics are on it, not to mention hundreds more from the Gameboy color and stuff. And if you need a bigger screen a Gamecube with Gameboy player is like what, 50 bucks? Plus you can play Gamecube RPGs, which, though few in number, are all really good.
I wanted to say that I don't see the PS3 really having any relevant exclusive RPG's at this time (FFXIII vs is far off still), as they have lost their exclusive FFXIII, and I can't even think of another one. I have noticed that the 360 (as mentioned by Cloud before) has a great selection, and the the US will get Tales of Symphonia II for Wii, as mentioned too.
But wasn't mentioned which I think is relevant, especially now, is this....I see a shift of the RPG's from home consoles to handheld systems. With Chrono Trigger making it's reissue to the DS, with SE doing their SNES/NES games to the DS, and with a new Dragon Quest going to the DS, it's probable that the RPG's are doing better on the handheld systems. The PSP even saw a reissue of the first two final fantasy titles, and got a prequel to FFVII. Not to mention both systems have tatics, and kingdom heart titles coming as well.
Personally, I'd love to see more RPG's come to the Wii, and hopefully they will. But if you want some really good quality ones, the SNES and PS1 had some of the best in my opinion.
I really hope FFXIII is fun, because I felt that FFXII was one of the best in the series since VII.