There's a good thing with Bards: They have a harp or so that always goes first when the turn starts, ALWAYS, and that harp can heal quite good, I heard. So if you need a godly support character, take a bard. Healing before the enemy even gets a turn is ownage. And they also have a song that takes 15% of the enemy's current HP, so your bard will be hitting for 9999 against the Cloud for quite a few turns. Or it's something among those lines. Bards also have a song that hastes the whole party, I believe...

And for the rest, what the others said: A good healer and stuff.
But bards are rummored to be godly in this DS remake. I haven't tried it (I don't have the game, darn), but the sources seem reliable.