Lightning was a female version of Squall aka she bored me. For me, memorable would be Snow. I'm not giving my reasons for not liking XIII anymore because they'll just get jumped on. I've played every FF from FF6(anthology), though I never finished FF6, but FF7 onward UNTIL FFXIII(I skipped FF12) they had no issues that were so bad that I couldn't continue playing after 4 hours. And I dont need to play an entire game to make full judgment. But when I bought the game I made the mistake of buying into the hype. Lesson learned, lesson learned well.
I have played all of them except the second number two. I have yet to beat the first two but this is a matter of opinion, I liked Squall too but he was more brooding and inward than Lightning who in my eyes was emotionally explosive.
My only complaint is it was to linear, that's it Snow was memorable as well as was Fang.
You have yet to play twelve you really should its a great game.