I thought the list was quite... strange. Here's mine:

1) Kuja (FFIX)
I'd put Magus here if Chrono Trigger was one of the series.
2) Sephiroth (FFVII)
3) Golbez (FFIV)
4) Gilgamesh (FFV)
5) Vayne (FFXII)

Interestingly, if I had to write a list of Top 5: Worst villains in the FF series, #1 would also start with 'K', and #2 with 'S'.