Looking for old-school turn based J-RPGs

Best of the bestfor me is Tales of Phantasia and Tales of Eternia aka Tales of Destiny II (yes this part have 2 titles depending of the place where it was distributed). The story is totally awesome. Fighting engine is superb and it was just so amazing when it came out. Also try Star Ocean and Final Fantasy. Really good game with awesome skill effect is Grandia and Grandia II

I enjoyed on XBOX360 the "Lost Odyssey".

First of all, Chrono Trigger is the high point for this style of game, so enjoy every last second of it. It is my favorite video game ever, and Chrono Cross is a huge disappointment by comparison.

That being said, here are some snes jrpgs that are your best bet:

Shadowrun (okay not j but worth looking into)
Terranigma (fantastic, often overlooked)
Final Fantasy 3
Seiken Densetsu 2 (aka Secret of Mana)

and most importantly,

Earthbound

(aka Mother 2)

E: for fun's sake, take a look at this trailer for an entirely fan-made faithful 3D recreation of Chrono Trigger. Sadly it never went anywhere because Square Enix are awful people with no sense of joy or love and sent them a cease-and-desist instead of hiring them :(

Chrono Trigger is one of the best rpg's ever made! Its gonna take you a long time to play through all the the endings.
I also loved terranigma and illusion of gaia for the SNES
Definitely try golden sun too!

I recommend Breath of Fire 4 - it doesn't stand out like some other RPGs do, but I found it one of the most 'complete' feeling RPGs I ever played.

Okay, I have far too many recs, but yeah:

PSP:
Legend of Heroes: Trails in the Sky (my favorite series actually, holding out hope that it will get a Steam release someday)
Tales of Eternia (have to import from Europe to get the English version, but this is easier to get than the PS1 version)
Ys Seven (while not turn based, is still very fun, also, grab Ys Origin and Oath in Felghana on Steam)

PS2:
Shadow Hearts
Shadow Hearts Covenant
Xenosaga I, II, III
Suikoden III, V
Tales of the Abyss

DS:
Suikoden Tierkreis
Golden Sun: Dark Dawn

GBA:
Golden Sun + Golden Sun: The Lost Age

Xbox 360:
Lost Odyssey
Tales of Vesperia
Eternal Sonata (can also get this on PS3 and that version has more)

PS1:
Suikoden I, II
Arc the Lad Collection (can get all three on PSN store for a low price, first two should be played together)
Final Fantasy IX

Sega Genesis:
Phantasy Star IV (can get this among many Genesis collections or by itself on Steam, go that route)

SNES:
Secret of Mana
Final Fantasy VI (marked as III on the SNES release)
Final Fantasy IV (marked as II on the SNES release) both of these FF games can be obtained in other versions, would advise the PSP complete collection for IV and the GBA version for VI.

And I'm sure I'm missing something, but those are some of the best games ever and all worth playing.