I'm kind of on a break, seeing as how I picked up half a dozen games from the Steam sale. But for me it's not really an FFXIV problem, it's just that I joined too late. There's technically a lot to do that interests me, it's just content that everyone's over (or has been over for several months).

I also recommend the hunts for upgrading Law gear, as while they're not brilliantly exciting they're better than running the same dungeons every day ad nauseam. Grab a friend or two and chat while you search if you can.

PVP also gives law, and if you're on Adders the queue times are usually short. It's not everyone's cup of tea, but it keeps you on your toes.

Variety prevents burnout.