Gonna throw another post in for Tales of Abyss since you already own it and it's one of the best games in the series, probably one of the better games (rpgs anyway) on the console as well. If it didn't have such jaggy graphics (heeeyy, ps3 kinda fixes this now with the new smoothing option it added so coo') and rather lengthy save times and load times on the world map it really would be the best or at least very close to being so.
Still, even with some of it's glaring technical problems the game itself is very solid with a very nice storyline overall (just enough melodrama to feel epic but not horrifyingly annoying) and the battle system is all kinds of fun.
Valkyrie Profile 2 is a breathtaking visual, audio and gameplay experience but the storyline is somewhat below average; however it's a worthy sequel to the original game (which also had a fairly shallow storyline experience imo) and stands up on it's own legs just fine if you've never played it. You'll be a tad confused at the ending events, but otherwise it should be just fine.
I highly suggest those two of what you listed; Shadow Hearts 3 is a bit of a disappointment compared to the first two and I just couldn't make myself like Grandia 3, either. The storyline and characterization was like a dumbed down Grandia 2 and the game completely fell apart for me about halfway through. Radiata Stories is funny and is a pretty decent game too, though, but I'd go for Abyss and VP2 first honestly. Very sublime games right there.
And there you have it. My very unorganized two cents. I blame it on being 2:30am and on my lack of will to go over and make sure this came out coherent.
Jam it back in, in the dark.