Let's not forget Mario and Luigi: Partners in Time on the DS! This game is so totally cute and fun. I hear it's kinda similar to Superstar Saga though I haven't played that. But using the babies too is pretty fun both in and out of battles, like solving puzzles on the field, and its a funny game
(Luigi is always getting left behind or dropping a baby or something silly xD)

And Paper Mario: The Thousand Year Door is the other I played, the thing I most like is how the battles are much more fun than traditional RPGs, using combos and different attacks, and all the items too, I didn't find myself getting bored of them.

And for both the graphic style is just lovely to behold