Suikoden V is my favorite JRPG for the PS2. The first 5-6 hours or so are a bit slow, but then it offer a great gaming adventure

Suikoden III and IV are ok too, but noticeably weaker than V (especially IV which is the weakest game in the series). Suikoden I & II for the PS1 are my favorite PS1 games, so generally it's a very good series I think!
Steambot Chronicles is another PS2 JRPG I enjoyed, and in some ways it reminds me of TES. There's a relatively large open world you can do stuff in, side quests and stuff, and it's all in 3D and realtime and after you finished the main story you can still continue to play the game doing side quests and whatever you missed. The game have two issues, though, which is the loading times and the sometimes very poor framerate. It's also the only JRPG I know of where you can side with the bad guys, but I never tried that. Apparently it have 4 different endings IIRC.
Yakuza and Yakuza 2 are very nice too. Yakuza 2 have arguably the best story of any PS2 game, at least as far as I'm concerned

The Yakuza games are kinda like JRPGs but takes place in present day and got a realtime actiony combat system ala Tekken or whatever. The combat in Yakuza isn't nearly as smooth as in Tekken, Street Fighter and so on though, but it's good enough.
Okami is an absolute masterpiece and possibly the only Zelda clone that is better than Zelda

I look forward to the sequel for DS that is released in about a month.
Ico and Shadow of the Colossus are very nice too, but they aren't really that long games and a PS3 port of those are released soon.