The filtration method that EK and BAng Guy are talking about is called the modified Berlin method. It incorporates live rock, live sand, and a good protein skimmer. You will need powerheads to circulate your water, but if done correctly, you will not need any outside filtration from wet/dry's or canisters or power filters. You put down a sand bed in the bottom of 4-6 inches deep, put on top of that eanough rock at the ratio of 1.75 pounds/gallon of water in your tank. Get a good, high-quality(although a bit expensive) protein skimmer, and that is your filtration. Your rock and sand will filter out any toxins that your protein skimmer misses. And being a DSB(deep sand bed) allows for anaerobic bacteria, that normally don't grow in shallow sand beds, to remove the nitrates, thus completing the filtration down to completely handle your bio-filtering. Most hobbyists find out(much later and after spending a lot of money) that they ended up with enough rock and sand in their tanks that they could have done this from the very beginning and not worried with other filtration. It is all a matter of personal choice, however. There are many options out there, this is just one of them. Wet/dry filters are very good choices, as well, and have the benefit of allowing you to move your other equipment out of your main tank and into your sump, thus making your display tank look better with less artificial distractions.
