Mike, The final fantasy series are great but majority are on the entertainment systems and not pc's. But since FFVII was made into a pc (best Final fantasy game IMO, so perhaps demand), but perhaps their are other games.
Final Fantasies are all separate games, so like VII has nothing to do with 3 or 4 or 10. Each game is its own story.
The first one i think was called Mystic Quest, Final Fantasy for SNES. It was a great "cartoonie" like story taking aspects from the first zelda games. Once you get into VII, VIII, VIIII (i didnt like nine), X the stories got more in depth introducing recognizable characters with full histories and branches of their own stories that came out after. Then FF XI, and XII got super in depth with amazing graphics. And finally XIII which is the MMO. (i never played XIII). FVII i would guess is the most in depth of its era, they made a prequel for it, they made a couple of side games for it. But FFVII for me, was the WOW factor of its time. Graphics might be a little subpar, but the story, open world game play, side quest, side stories, and just the amount of share things you can do, to me has never been matched in any game. (Skyrim is probably closest, but after a while skyrim got repetitive.. Look another dragon...)
If ever given the chance, i would highly recommend FFVII, then FF3 for SNES, and FFXII for PS2. Or those all may be available on pc now and i just dont know.
-Todd