The best filter is the one that you, the custodian, are most comfortable maintaining. If by "the best" you are referring to efficiency, I believe you get more for your money with a sump. A sump allows for expansion with minimal change to the overall system. Canisters can be efficient, but to get the same turnover in a given system, a sump just needs a bigger pump. There aren't very many canisters that you can modify with bigger pumps. That being said, a sump on a smaller tank, say under 50g, really isn't going to be much more efficient than a nice canister.
In the end, whatever gets the job done and you are most comfortable with, that's the filter for you. Sump filters and many canisters can be somewhat intimidating to setup and maintain. If the fish you want to keep require certain filtration, like a protein skimmer and you arent comfortable or familiar with its use, maybe an "easier" fish should be considered at first.
Jus ma 2.