Most would agree and argue that a sump is the best way to go for a reef tank of that size. Is the tank pre drilled for a sump or would you have to do an overflow box? Oftentimes, on a reef tank with live rock, biological media is not needed in the filter whether it be bio balls in a sump or some other type of ceramic media in a canister since the live rock does the bio filtration for you and ends up making the system much healthier and flourishing.
You might get away with two high-end canister filters like an Eheim or the new Marineland canister series (like the C-360). Either way, one Emperor will in no way be enough filtration for a 100 gallon reef.