Squall of course is the best in the game. He is virtually unaffected by Blind (although you lose the ability to trigger if you are), he deals at least 1.5 times as much damage as everyone else if junctioned equally (until you reach higher levels that is) and he has (arguably) the best set of limits in the game. For me, Squall has the abilities, Attack, Magic, Draw and Recover. Never fails me.

Zell is my other party member, a trump card, usually. I usually won't use Armageddon Fist unless I really need it, otherwise, he just sits there and heals. He has Attack, Magic, Treatment and Revive.

Rinoa is my final member, I don't learn Wishing Star purposely just so she uses Invincible Moon more often. Without junctions, Rinoa has the highest strength stat (although Squall does more damage) and if properly used Angel Wing is devastating. I give her Attack, Magic, GF and Item.

I don't use Quistis. That's it. Nothing that makes her good.

I have a tendancy to skip the spell I wanted when using Selphie's Slot (hehehehe) so I don't use her either.

Irvine's alright. I'm a cheapskate, and I can't be bothered buying ammo for him or refining it.