Wow, FFVIII is leading, which is quite weird. I disliked drawing spells, drawing more and drawing even some more after that, and I didn't expect many people to like that. The greatest magic system... well, I'd say FFVII because of its materia system, but since you can have every character cast every spell and that way have overpowered characters that deal huge physical damage while casting Cure 3, Life 2, Big Guard, Ultima and Knights of the Round, I'm not really sure.

If not FFVII, I'll probably go with FFIV or FFV. In FFIV, white mages were good with healing spells, black mages were good with offensive spells. It was usually a good idea to have both in your party, so neither of them is a useless character. In addition, I thought FFIV was so hard that you needed to use every bits of strategy, so I used spells like Slow, Break, Toad, and Mini on enemies while using spells like Haste, Berserk, Protect, Reflect etc on my own characters. I find this a benefit for the magic system because normally I hardly ever use status spells, but in FFIV, most of the spells become handy during the game.

I mentioned FFV above. Why is that? It's because you can use the job system to mix spell types and have a character use different kind of spells, while still nobody is overpowered, and nobody is a carbon copy of another character (unless you really try and level them up the same way and use the same jobs and abilities). There's a plenty of good combinations. White and Black Magic together (Holy and Flare, healing when needed), Blue Magic and Time Magic together for some handy tricks (Haste 2, Big Guard and White Wind, anyone? Not to mention 1000 Needles / Blow Fish is one of the few things that can destroy Harpies and Skull Eaters on World 1), or one of my favorite combos, X-Magic, Summon Magic and Time Magic (Quick, Haste 2, Golem, Meteo, Bahamut spam etc). It's really fun to mix and match things in FFV.