Best of those I've played: VIII
Worst of those I've played: VII

Despite that, VII remains my favourite game of all time. Endings aren't very important to me, they're more of an added bonus if things go well.

I find FF endings are in general fairly terrible and in possibly every instance (bar possibly VII, due to the minimalism of what we find out from it) the endings don't exactly make sense. VIII and XIII already have been pointed out for their reasons, both perfect examples of this. But I don't really mind that - I find that in games full of magic, nothing is ever really going to make that much sense. Basically from what I've seen, it's a case of "Look, you saved the world, okay? Now shut up and watch the pretty scene." And that's that. Which is probably why it's so rare that I finish an FF game. I also don't finish some because I like to do sidequests etc. just before the end because I know the game is OVER once you beat the final boss (XIII an exception, hence I finished it pretty quickly).