absolutely, in fact you should definitely eliminate the canister filter. A good supply of liverock (1.5 to 2 lb/gal), good flow in the tank (from your powerheads and proper rock arrangement), and a quality skimmer should be the foundation of your filtration. Optional things to add for filtration include carbon reactor, phosphate reactor, UV filter, and deep sand bed. The carbon and phosphate reactors are similar to canister filters, built for holding activated carbon or phosphate absorbing material. A UV filter helps kill free-floating parasites and bacteria (depending on the flow rate through the UV unit), helping to fight the spread of disease in the tank.
And as far as the sand bed goes, definitely don't use crushed coral, use a sand substrate, aragonite sand is a great choice. Most importantly, choose the depth of your sand bed carefully: either use 0.5 inch or less, or 4-6 inches. Don't go in-between, the 0.5-4 inch range is deep enough to trap waste and allow it to pollute the water, but isn't deep enough to grow anaerobic bacteria which will help keep your nitrates at zero. If you want sand but not a deep sand bed (just for looks sake), then go with 0.5" or less that way it isn't deep enough to really trap wastes. Otherwise, use 4 or 5 inches of sand, and in time certain bacteria will grow in the deepest parts of the sand bed where oxygen can't reach, and it will consume nitrates and convert it into harmless nitrogen gas. If you choose to go with a deep sand bed, then be sure that you don't disturb the sand bed when you clean your tank... no need to vacuum the gravel. You can keep things such as nassarius snails, sand sifting starfish, and other sand stirring creatures to help keep the sand bed stirred up naturally and the upper layers clean of detritus and other wastes. Nassarius snails are really cool by the way :-D