Here is how it should go down

FF Games
FF I
FF IV
FF V
FF MQ
FF VII
FF VII: Cerberus
FF VII: Other(By the time advent talk dies out crisis core will start coming up)
FF IX
FF X
FF XII

The Rest of the crap
FF II
FF III
FF VI
FF VIII
FF X-2
FF XI
FF Tactics
FF The movie no one saw
FF Music
FF General

Other Squenix games
Xeno
Chrono
King DAM Hearts
General Squenix