Crystallis was my first major gaming experience (given to me on same Christmas as Mom bought our NES)... but it was only an afternoon hobby until my first real gem fell into my hands.
(To bastardize a quote from Scotty, from his TNG episode...)
"Final Fantasy. No bloody II, III, IV, VII, or other numeral."
Pick four adventurers. Name them. And the world is yours, one mode of transport at a time.
My first party was the standard Fighter, Thief, White, and Black... But I think I had the most fun with the Black Belt and Black Mage twins set. A quick double cast of FAST, and the Black Belts were melee masters... and then just mop up with the Mages.
By my third or fourth playthrough I'd heard about the Power Level Peninsula (a 3x2 space where the monsters were calculated from the tables of the next continent to the north... WAY above the normally available Ogres and Creeps. ZomBulls, GrOgres, and Ogres by the screenful, perfect to grind through the EXP and GOLD needed for growing casters. I think I hiked out there for a good week, slowly incresing the number of Tents I could bring along to make the trips last longer.
I'd played on a friend's Atari as a kid and I played SMB and a few other games on the family's NES for fun, but Final Fantasy was the turning point for me... I knew I had my life-long hobby, even at the age of thirteen. Sadly, the poster-sized map/creature index literally fell apart from being folded and unfolded so many times over the years.