Im sorry DocTim, but i have to differ with you on the idea that filtration differs from any number of fish one may have, for freshwater you not need as great a deal better in your system filtration system, but moving on over too marine tanks demands a great deal better in filtration methods. But of course it is always a debate many will differ from or in ones opinion.
itzazoo, if you are to go with a 65 gal tank, you want to have a sump with the best skimmer you can buy for it, for stay away from canister filters for their nitrate traps where as a sump, the larger you can go would add a great deal your tanks water volume, and skimmers in sump are a great deal easier to clean then canister filters. Also to add to that, if you gotten a canister, you still require a HOB skimmer, so you don`t require both, just a good skimmer.
Buddy