Cloud vs. Zidane- Cloud assuming we take AC into account
Vincent vs. Amarant- Vincent
Cid vs. Freya- Freya
Aeris vs. Garnet- Aeris
Yuffie vs. Eiko- Yuffie not taking the FFX summon system into play
Barret vs. Steiner- A gatling cannon can take out a suit of armor in no time.
Tifa vs. Vivi-Tifa. Tifas faster and 1 or 2 hits and Viviis gone.
Red XIII vs. Quina- I lol'ed. Red XIII of coarse.

Of coarse I'm a shameless FF VII fanboy so my opinion is biased. Heavily biased.