This list is invalid because FFT is not on it.

FFIII is a very curious choice. FFV and FFT both have far superior job systems. Mine would be:

1. FFI - The original
2. FFV - The first really good job class implementation. FFT would go here instead if it was on the list.
3. FFVI - A classic with arguably the best story
4. FFVII - Possibly the most significant entry in the series after the original, making FF mainstream
5. FFXII - I figured I should pick an FF from the newer generation, and FFXII is by far the best.

FFIV and IX warrant honorary mentions.