You could also get Tales of Graces, or you might want to wait for the PS3 version
Looking at your game collection, the Wii is your first Nintendo platforms, so I would really recommend getting some Nintendo points and to download some classic games. As you like RPGs, the likes of Secret of Mana, Super Mario RPG, the 2 Ogre Battles, Shining Force 1 and 2, the Phantasy Star games and Romancing SaGa are highly recommended. (Haven't played the last one as it is Japan only, but I've heard only good things about it)
You don't seem to have Okami for your PS2, that is definitely worth a purchase
As you don't have a Gamecube, get some GC games, either by Wii re-releases (such as Pikmin 1 and 2) or buying them in original format.
As you've got Disgaia, you might quite like Fire Emblem: RD, but you might want to play the GC one before
The likes of Super Mario Galaxy 1 and 2, Zelda, Metroid, Little King's Story and SSBBrawl are amazing, but I'm sure you'll hear that from almost everyone else