In terms of visuals, anything after FFIX is pretty boring actually, with the possible exception of the -aga spells from XIII surprisingly enough. FFI wasn't so great either.

In terms of actual usefullness, VII is the game where I don't really use magic at all that isn't enemy skill or summon and even those I don't use too much thanks to Limit Breaks and your party's natural high melee damage output. Barring the Junction system, offensive magic in VIII is atrocious as well. So VII and VIII probably have the least useful magic for my playstyle.