It might just be my bad luck or fish-keeping skills, but I have to disagree with Y2SAYS. I think a reef tank w/o fish is easier to maintain than a fish-only tank. With FO, you have disease to worry about. To do this right, you either need a lot of luck or a QT tank. So add a QT tank to your maintenance list if you want FO. You also have to have fish you can catch when they get diseased. This can be very difficult and stressful to the hobbiest sometimes.
Maintaining a reef is not difficult once you get past that tank maturing stage (2-6 months after end of initial cycle assuming nothing else changes during this time, like adding more LR, LS, etc.). I hardly check my chemical levels anymore because every time I check (now about once every 2 weeks), they are still the same. I just watch the critter behavior and if they start acting weird, I check all the levels. Feed corals and inverts once every 2 days, drip kalk for 5-15 minutes each night, and that's it.
I would go with reef and no fish. As mentioned, it can be fascinating.
Cheers,
kris