The monthly fee's left me with a dilemma, and I don't know if I'll even be able to play XI.

However, unless the price is totally unreasonable, I've come to the conclusion that I shouldn't deny myself such a game. If I didn't play (and complete) XI, I'd always feel kind of empty.

Cheesy statements aside, I don't really see why FFXI should be left out of any FF fan's collection. In your case specifically, I think it's important that you complete every FF, including XI. It's a great achievment, and a fun one, too.