I really really like this game - another FF?

Right, got my mitts on a 2nd hand PS2 :) So game shopping methinks....

Take the dive. Play FFIV.

I feel like VI has stood the test of time quite well. Actually, IV as well, even though I haven't played it anywhere near as much as I have VI.

FFVI is great, as well, though I certainly would suggest playing FFIV first. Doing so the other way around would sort of subtract from FFIV's greatness. :p