My team remained more or less unchanged once the game stopped forcing you to change:
Zidane - You're forced to use but what's the problem? He's speedy and deals good damage so no complaints from me.
Freya - I've always liked Lancers/Spear using characters so Freya's a natural choice for me. Plus Jump spamming made necron a sinch.
Quina - The mightiness of Quina cannot be disputed, arguably the coolest Final Fantasy character aside from Kain and Balthier.....well, in my warped mind.

But Blue Magic rocks, and stabbing people forks does as well.
Aramant - Visually he was the character that made me think "....cool" with in the game. That and he seemed rather balanced so it wasn't a bad deal.