Jason has had to deal with a lot of people over the years. He's had to fight many different kinds of people, but only a few of them were actually worthy opponents. So, the question is:
Who gave Jason the best fight?
There are, I'm sure, many different opinions on this subject. But here, of course, I will give you mine. I'll run through the ones I think were worthy opponents, and then we'll see who was the best.
Tommy Jarvis - In Friday the 13th: The Final Chapter, Tommy was a young boy obsessed with horror special effects. He made his own masks and such, and in the end, it helped him defeat Jason. He cut all his hair off and made himself look just like Jason looked as a child. It confused him just enough so that Tommy could attack. This led us to believe that, since it was supposed to be the last film of the series, Tommy would "take over" for Jason. In the next film, Tommy was older and locked away in a mental facility. People started dying, and I think the idea was to make us believe that Tommy HAD taken over for Jason. But in the sixth film, Tommy was all grown up, released from the facility, and back to fight the monster once again. See, this is my point. Tommy survived through three of the films. There's always someone to survive in each one, but they never come back in the next (apart from Alice, but she didn't last very long). Tommy kept coming back, and he was never killed by Jason. He hasn't been seen since the sixth film, but he just disappeared; he wasn't killed. Despite the fact that it actually wasn't Jason doing the killing in part 5, I think it's impressive that he could survive through so much, where others failed.
Tina - In Friday the 13th: The New Blood, Tina was a young woman with special powers: telekinesis. She's had these powers her whole life because of a traumatic experience as a child (her father died and she blamed herself), and she's gone back to the lake to face her fears. Along with her mother and a doctor, she wishes to learn to control her powers so she doesn't hurt anyone else. But she starts seeing things: scenes of the partying kids next door being murdered by a monster that she's telekinetically released from the lake. So, instead of controlling her powers, she must unleash them on Jason in order to survive. We all know that Jason isn't the brightest crayon in the box, so mind power is pretty strong over him. Tina's was strong and, since she could hit him from a distance with all sorts of objects, she gave him a pretty good fight.
Kay-Em 14 Kay-Em 14 is from Jason X and she is a fembot. She was created by one of the little nerdy boys on the ship, to be used as a sexbot. But we learn quickly that Kay-Em 14 isn't only good for sex - she's also quite a badass. Since she's virtually indestructible herself, there isn't really much Jason could do with her (or to her). She pulls out the big guns (literally), and blows Jason to pieces. I was actually quite pissed at the fembot bitch for hurting my husband, but all was well in the end.
Freddy Kreuger - Of course, we couldn't leave Freddy off the list. I addressed this one in my last Friday the (not-so) 13th, but we'll go through it again. Freddy is the dream demon, he is the master of mind-trickery. Because of this Freddy, like Tina, gave Jason a hell of a fight. He, unlike anyone else, was able to actually throw Jason around like he was nothing. He also got into his mind and fucked with him a little bit, which actually isn't really saying much. Plenty of people have fucked with Jason's mind over the years, but none quite like Freddy.
I think these four people gave Jason bigger fights than anyone else. But who takes the number one spot? Is it Tommy, the young boy who survived more through more than anyone else? Tina, the girl with special powers? The fembot Kay-Em 14? Or Freddy Kreuger, king of dreams?
Winner: Tommy Jarvis
Tommy takes the win not because of how much damage he caused, but simply because he made it through more than anyone else. He's the only person in the entire series to survive through more than one film. Also, every good horror villain has to has a nemesis. Michael had Laurie, Freddy had Nancy; Jason has Tommy. So, there we have it. Even though some others caused Jason much more harm than Tommy did, Tommy gave Jason the best fight, because he had to deal with him for so many years. And Tommy wound up knowing everything about Jason; he'd dealt with him before, he knew how he worked and how to defeat him. I think in the future, whoever Jason has to fight should locate Tommy Jarvis for advice and guidance - because no one knows Jason like Tommy.