I went with Celes only because it's who I had leveled up more and therefore she was the power hitter of the females in my party. When I ran through my initial play of FFVI, I had an all-guy 4-some, but Celes came in to clean up as a 5th hitter if one of my main 4 went down early. Actually, in the final fight against Kefka, she was the the one who delivered the final blow to conquer the game for me. that was 11 years ago, and I can't believe I still remember that.

Celes > Terra