Originally Posted by
Kawaii Ryűkishi ^ It's the song that plays during the bridge-crossing scene in the first game. It's hard to pin a definite name on it since it usually sports a different title from game to game, from "Opening Theme" to "Prologue" to simply "Final Fantasy." Furthermore, FFVI started a tradition of mixing it into the song that plays during each game's ending credits instead of letting it stand on its own. (FFXII thankfully diverts from this pattern, although you can bet it'll be reinstated for FFXIII, if the theme is even allowed to make an appearance at all.)
The song plays in every numbered FF except for FFII, FFX, FFX-2, FFXI and FFVII DoC. It's also missing in FF Tactics games and the movie FF: TSW. I'm not sure about FF: MQ and FFCC. However, the song is played in FFVII AC. I usually call it just "Final Fantasy" because that's what it's been called lately (FFIX, FFXII, FF Concert 2002 and More Friends Concert). The song played during the opening in FFs 1-4, and the opening menu in FFXII, but ever since FFIV, it has played either during the ending or the ending credits. It also played during the ending credits in FFI WSC/Origins (and DoS?) and FFVII AC.