I really really liked FFV to FFX, and FFXI gave me a unique enough experience to always be remembered. FFIV I still consider memorable even though it's not as divine as the others. FF1 is a game I forgot quickly and never picked up again. FFXIII might fall into this category in a couple years as well, I don't think I'll pick up that game again when I'm done with it.

Just FF1 for now, I guess!