I love FF 1-9, after that, I'm not a fan.
FF7 is the best in the series, followed by FF9 and FF6. FF8, although good, is the worst out of 1-9.
FF10, 11(MMO), 12, 13, 14(MMO) were all not that good in my opinion.
If you are playing FF7, then be prepared for one of the, if not the greatest JRPG of all time. The story/characters/weapons/leveling system don't fully open up until about 10 hours into the game, that's when you realize how amazing the game is, and it never stops from there.
“Anna, my strong, terrifying Anna.” -Cas
"You lack the requisite spine and testicular fortitude to study under me" -Elodin