PS2 hands down. Thread closed.

PS1 with a closed second.

SNES with a far third place.

DS slowly growing into a contender.

SNES/DS/Dont know/PC

1. SNES (quality) PS2 (quantity, lots of quality too just not as much as the SNES)

2. DS by a HUGE margin overtakes everything this generation in the amount of JRPGs (home and handheld). Square Enix has 15 JRPGs on or being made for the DS, even Bioware has an RPG coming for the DS (Sonic RPG), and many other companies such as Capcom have many RPGS made or coming to the DS.

3. No clue

4. I don't personally care. I think any platform from DS to PS3 can have a good or great RPG made on it. Great RPGs aren't built off of amazing system capabilities. They are built on plot, gameplay, and originality. I can still go back and play Chrono Trigger and enjoy it more than any RPG that has been made since then. So, in conclusion: It doesn't matter, it's up to the developer to make sure the RPG is high quality no matter what system it is on.

 And the 360 is too.

1. SNES - Final Fantasy IV and VI, Chrono Trigger, Secret of Mana, Earthbound, and others I know I'm forgetting. whatever the case, two fo the best RPG's ever made--FFVI and Chrono Trigger-- were for the system.

2. Right now, neither really. I would give the DS the edge only because it can play FFIV and FFVI for the GBA but other than that, there's nothing original and impressive on either (and I even count FFIII as original). That might change when the remake of FFIV is released, but we'll see.

As for the countless remakes of FFI and FFII on the PSP: FFI and FFII are bad games. Good for their day, but they haven't stood the test of time. About the only reason to play FFI is for pure nostalgic reasons and nothing else.

 3.  There use to be countless RPG's on the PC, only they were called point and click adventures.  Sadly, that genre died (though hopefully it's going to make its long awaited comeback).

4.  no one console is really better for an RPG than any other.  I suppose handhelds are my personal favorite because I like being able to take them with me when traveling, doing mundane tasks, and so forth. 

On the current generation the 360 is the best, but still a long way to go!!!!!

Current Gen Handhelds DS, right now for overall RPG's 360, best chance right now of gaining the most RPG's Wii. Japan loves the whole casual thing and adopted the heck out of the DS, no reason that won't happen with the Wii too. Where the Japanese go the RPG's will follow. So right now the Wii has the best chance of getting the most JRPG by the end of the gen.

Yeah, as others have said, PS2 or DS is your best bet. 360 is the best so far this gen, but is no where close to PS2.

Interesting question.  In fact, it wasn't always like that.

Back in the mid-1980s, there were many J dev studios that produced quality RPGs for PC, such as BPS, XTALSOFT, T&E, and I played theirs enthusiastically.  Square also produced games on PC (they were a very small studio at that time).  Most of these studios disappeared during the early 1990s.  Only a few survived such as Falcom, KOEI, and obviously Square. 

These companies survived because they shifted some of their resources to the console market.  Square ditched the PC market almost entirely and went to console all out.  Those who did not adapt to the surge of the console market, which Nintendo created, just went out of business.  Because most J developers have shifted their resources to consoles in the late 1980s, the PC game market remained underdeveloped even until today.

Currently, when it comes to PC gaming, there are two types of audience in Japan, gamers who enjoy MMO/FPS and those who play eroge (hentai games so to speak).  The number of the former is dwindling, and the latter just got nothing to do with real game.  Even among the former group, American titles have not been very popular because they generally prefer Anime-like character/environment designs.

Evidence to support PS1/PS2 RPG dominance

Xenosaga 1,2,3
Dark Cloud 2
Dragon Quest VIII ( i would dare say it was the best RPG of the last-gen consoles)
Star Ocean: Till the end of time
Valkyre Profile 2
Rogue Galaxy
Final Fantasy XII, X, X-2
Kingdom Hearts 1,2
shin megami tensei: digital devil saga 1,2
shin megami tensei: nocturne
shin megami tensei: devil summoner
suikoden III
Tales of Legendia, Tales of the Abyss

Also the PS1

Parasite Eve 1, 2
Xenogears
Final Fantasy Tactics, VII, VIII, IX
Suikoden 1, II
Grandia 1, II
Persona 2
Valkyre Profile
Vagrant Story
Chrno Cross
Star Ocean 2
lunar: silver star story
breath of fire III