Thief from FFI - Thought Black Belt and Red Mages were better.
Edward from FFIV - If built right he can be the most powerful ally. (ports where he is end game)
Gau - It takes a lot of time to learn all the rages. After so long on the Vedlt I learned that, A. I can learn rages and B. I can learn spells without leveling up making stat maxing even better.
Yuffie - My mains were cloud, barret, and cid. After learning to morph I grew strongly attached to Yuffie and her "Doom of the Living" Limit break.
Rinoa from Final Fantasy VIII - Only teach the dog "Angelo Search" and you can use a glitch to obtain tons of rare items.
Yuna from FFX - She seemed so weak but giving she can have multiple limit breaks cast without breaks is what made her so unique and in my eyes the best FFX character.
Penelo from XII - believe it or not she can run faster then others. (or maybe it's all in my head)
Hope from XIII - I hate the character but in battle he can be a good RAV, SYN, MED.

that's all folks!