.hack//G.U. - Vol.1//REBIRTH
.hack//G.U. - Vol.2//REMINISCE
Everything that appears in those two reviews is what I know about the .hack games. I personally prefer the mangas, but that's me.
About the others, you can get Odin Sphere on PSN nowadays and Breath of Fire: Dragon Quarter is not for everyone but I'm pretty sure is one of the better RPGs on the PS2 if you give it a chance.