I will say Lost Odyssey, FFX and Tales of Vesperia.

Today i will probably buy Demon Souls, it looks like a great game like the others you need to give a chance.

Lost Odyssey.

It's much more traditional and (in some ways) restrictive than most JRPGs released this gen, but the writing and characters make up for it. I recommend it without hesitation. Get past the first hour and the game opens up like like you wouldn't believe.

Trust me on this one: Persona 4.

Final Fantasy X

Let's see:

Lost Odessey
StarOcean 3 & 4
Final Fantasy X (similar in some respects to XIII)
FFVII-IX on PSN for a bit of history
Vagrant Story on PSN
The Grandia games were good, I think 2-3 were on PS2, 1 on PS1.

If you ever get a DS or have a PC with a SNES emulator then play Chrono Trigger. It's just plain fantastic. Same for FFVI.

Thank for so many recommendations. I won't be able to play any PS1 games however. I'll look into getting FFX, my store may have it. Lost Oddessy seems like the other one everyone is reccomending so I will go for that too

All Mistwalker games
and all of Level 5 games
also all Final Fantasy games and JapanStudio games

FFIX
Tales of Symphonia
Baiten Katos
FFVI
Chrono Trigger

Edit: after reading that you have only played those  i want to give you my most sincere and heartfelt condolences.

OT:

you wont like jrpg if you liked FF13 but here are some classics

16bit
chrono trigger
Final Fantasy 4, 6
Breath of Fire 1,2
seiken densetsu
legen of legaia
tales of phantasia

32 bit
xenogears (one of the best stories ever)
legend of mana
FF 7,8,9
tales of destiny
grandia

128 bit
FFX
Dragon quest VIII
rogue galaxy
kingdom hearts 1,2( this are not pure RPGs)
xenosaga 1
start ocean : til the end of time

I say go with Lost Odyssey first. I am.... not in love with FFX.