Sorry about the delay, I suppose I'll be making more than one post in a short amount of time. The only reason this hasn't happened sooner was I honestly had to sit down and think what character possessed the personality, determination, and reason for fighting that I deemed the "best."
WARNING: There are spoilers beyond this point.
Tidus
This came as a shock even for myself. Many friends of mine would consider my favorite character as being Link or even Squall or Cloud, but let's face it. Those three characters combined lacked any form of personality compared to a normal human being. We get it, you're a brooding hot-shot inexplicably thrown into your current situation and what do you do? Just deal with it. No questions asked.
For those that know nothing about Tidus, he's from a little video game series called Final Fantasy. Don't know if you've ever heard of it, but they have a couple games out, and his was specifically the tenth volume. Starts out Tidus is a blitzball player--a sport that appears to resemble underwater football--that lives in a highly advanced city known as Zanarkand. Big monster comes, Zanarkand is destroyed, but he makes it out alive thanks to aid from a man named Auron. This is where you start to see the formation of Tidus' personality, which was rather hit or miss. Some people considered him a whiner or too vocal as the lead character, but this is primarily the reason why I say he's well-formed.
If I was personally tossed into a situation where monsters started attacking me while some weird old guy chucks a sword at me and tells me to hit shit with it, I would honestly panic/question what the hell is going on. Tidus constantly does this throughout the entire series, practically mouthing everything the player wants to say, but can't because we're not a character in the game. He tries to fit in, but since he knows nothing about the current time or history he comes off as stupid, when he honestly just doesn't know since he's from 1000 years in the past.
Perhaps the most interesting aspect about Tidus, is his constant struggle with trying to understand the fate of summoners and their destined link with Sin (the bad monster). Furthermore, what he does when he finds out what happens when summoners reach the end of their pilgrimage. Having fallen in love with the woman he escorts essentially to her death, instead of completing the "Final Summoning" to destroy Sin like every other summoner before her, he fights against it, saying he'll find his own way to destroy Sin, once and for all. This fight against fate occurs in many games, but why he does it is a completely different reason than say Chrono Trigger, where it was out of necessity to fight Lavos. Tidus didn't have to make the decision to abort the "Final Summoning," because Sin would have died regardless and there would have still been a time of peace, albeit temporary. He makes his decision based on his love for their summoner, Yuna, and because he realizes his father, a man he used to hate and has grown to respect throughout the course of the game, has become the most feared monster of the world, Sin. It is because Tidus takes the step forward to break the cycle that he deserves his title of "hero."
I still give my respect to Link, Cloud, Serge, etc. because they did what they needed to get the job done.
I also want to give a shout out to Wanderer of Shadow of the Colossus. He was a close contender for the spot granted to Tidus for almost the same reason. I won't spoil anything about the game, but you should definitely play it, and those that have I'm sure understand why I would bring up Wanderer in such a circumstance.