VIII. ♥ Not only is it my favourite Final Fantasy game, but it's my favourite video game of all time.
UNO; The characters were so well designed and developed so well over the course of the game. A notable example of such would be Quistis Trepe (who is also my favourite character, personally), and Seifer Almasy. The characters just seemed more realistic to me in this installment than in others (perhaps not in terms of appearance, but personality) - people who can be easy to relate to. They are (and really do act like) your typical teenagers, each with their own obvious flaws, adapting to constant changes in their environment.
DOS; The world this installment takes place in is beautiful. My favourite places would have to be the small town of Winhill and the garden shown in the intro FMV. While the graphics are nowhere near spectacular compared to video games of today, the settings look great, from your starting point at Balamb Garden, to the location of the final boss.
TRES; I'm going to admit it: I'm a sucker for those romantic dramas, and FFVIII is exactly that. It's not only a tale of sorcery and magic, but a story of romance. I also see it as a story of self-discovery, as each character comes to terms with who they are as people over the course of the game.
CUATRO; I know some people complained about the gameplay (notably the junctioning system) being too complicated, however, I rather liked it. Although it's not as easy to grasp as other systems - and I must admit, I prefer both FFVII's materia system and FFX's sphere grid system over the junctioning system - it still has its strong points. I actually like how you can "draw" magic from enemies instead of using MP - it makes magic much easier to find and use. Junctioning magic to various stats is essential to the development of your characters - and since it is much easier to find stronger magic in FFVIII, characters can become much stronger much earlier in the game.
I know, I went a little go-hard with this post, but I really couldn't resist. ._.;;