Vesperia, hands down. I love that game <3 I'd really like a translated full version port from the PS3, though
Lost Odyssey and Eternal Sonata are quite good too. Haven't finished either, since I had to give the xbox back (was borrowing it from a friend), but still had lots of fun.
Couldn't really get into Infinite Undiscovery; Resonance of Fate was mediocre... What else...
Oh, Star Ocean. Well, it was quite fun from the gameplay perspective, BUT.
I absolutely hated the little girl character, especially the voice. Ugh. Still sends shivers down my spine. Another big gripe I had with SO was the graphics. The visuals just look too perfect - twinkle-twinkle, sparkle-sparkle, glitter-glitter. The sterile perfectness even surpasses the level of the Final Fantasy titles and that says A LOT. Of course, that's personal preference, but I really disliked this aspect. Finally, getting back to the characters... Well, to put it shortly, the characters were total cliches. Anyone who has seen several anime series that involve a cast of teens fighting for one cause or another can attest to this.
Overall, a 7.5 in my book. The gameplay is fun and the plot is decent, but the characters are generic and [opinion] the graphics are too perfect[/opinion]. The metacritic score (72) pretty much fits the game like a glove.