Going by the Final Fantasy games I've actually played and had distinct casts of characters (FF1 only has "jobs" and that's it), I typically have one favorite male and one favorite female in each one:
FF4: Cecil & Rydia
FF5: Galuf and Reina
FF6: Terra & Locke
FF7: Tifa & Vincent
FF8: Laguna & Quistis
FF9: Freya & Zidane
FF10: Auron & Lulu
FF12: Fran & Balthier
FFT: Beowulf & Reis
Final Fantasy 14 is a bit harder to decide because aside from the cast being much larger than the rest, most of them aren't "playable" in the traditional sense like previous characters, and I haven't actually "finished" FF14 so I can't really give most characters a final verdict yet.
