There are few people who would deny that the Final Fantasy series has some of the most memorable JRPGs of all time. Final Fantasy fans are so passionate that they spend a great deal of time arguing over which ones are the best and which ones are the worst. In my eyes, this is one of the best . Final Fantasy VII might have a better story and more memorable characters, and XIII certainly has the best graphics, but X, hands down, has the best gameplay.
The story is bizarre, to say the least. It's about a giant whale (for lack of a better term), named Sin, that keeps attacking the land of Spira, because of their past use of forbidden machina. It follows the tale of Tidus, a blitzball player who gets caught up in the struggle of defeating Sin and the fiends it has spread across the land of Spira. Along the way, you'll join up with Yuna, a girl who dreams of becoming a summoner, Auron, a bad ass with a sword who was friends with Tidus' father, Kimari, a once proud warrior who was shunned by his people, a beatnik blitzball player named Wakka, Lulu, a goth mage, and a young girl named Riku. Each character has their own unique abilities that are spread across a giant ability tree called a sphere grid. Riku is a thief, Auron a swordsman, Wakka a ranged attacker, etc.
The combat is pure turn based action. There is no ATB gauge, and as a result, the combat is slower paced, but it is ultimately a masterpiece of a strategic battle system. I prefer this style of gameplay over the ATB gauge, and I don't even want to talk about how the battle systems are absolute garbage in XII, XIII, and XIII-2. Hironobu Sakaguchi is sorely missed, after his departure from Square Enix in 2004, and the series just hasn't been the same without him. If you're looking for a JRPG in this generation that's similar to classic Final Fantasy, I recommend Sakaguchi's Mistwalker Studios game, Lost Odyssey.
Final Fantasy X is linear, up until you get the airship anyways, but the environments are varied, and they are absolutely the most beautiful environments I've ever seen in a PS2 game. The fiends you fight are stunning, as are the summon creatures, which are called Aeons. There are also a variety of mini-games you can play, such as Blitzball matches, as well as the various and difficult mini-games it takes to power up your characters' ultimate weapons, and you can spend countless hours capturing fiends to unlock massive boss battles in the monster arena that are much harder to beat than even the final boss.
If I were to sum up Final Fantasy X in one word, it would be "magical." I spent over 300 hours on this game; more than any other game I've ever played, aside from the MMO games Guild Wars and World of Warcraft, and I enjoyed every second of it. This is the game that got me hooked on JRPGs and RPGs in general, and it is the gold standard by which I judge all other RPGs.