Hello Kcarlson, well choosing the right filtration method that will ultimately make you happy is on that comes with many approaches. Depending on the type of Marine Aqaurium you are intending on keeping will get you started on your endeavors. Ask yourself these questions:
1. What will you be choosing as for a setup? Fish Only with Live Rock setup or a Reef setup.
2. How much are you looking to spend for the filtration setup of your tank without neglecting the other aspects such as subtrate, lighting, aquascaping, etc. etc.?
3. What type of fish will you be considering to live within your aquarium? Are they extremely efficient at creating high amounts of waste that will pollute your water or are they small and the waste created is negligable?
4. How much space either within the tank or underneath/around the tank are willing to allocate for the tank.
These questions will help guide you toward the right purchase for your tank. Everyone has their own idea of what filtration is the best and everything works out sometime differently for different people. I myself combine massive amounts of filtration including Hang On Tank style Emperor Filters, Protein Skimmer, and Canister Filter and don't use a sump. Other have an approach that is just live rock with a Protein Skimmer or even those that have a sump along. Its a different setup. We can just point out what has worked best for us in our situation. I hope this helps.