you definately want a filter - -3-4 times the size of your tanks IE.....200-300 gph - you can use a couple hang on back filters or get a canister or set up a sump preferance right now . . .hang on backs are cheap and easy but ugly canisters are good work horses but a lil more labor intense for servicing unless you spend a lot of money for a high end one and sumps take up room can be noisy but are the most effective and natural and more condusive to changes, experiments and upgrades plus it adds that much more water to your system.
live sand is simply sand harvested from either the ocean or established tanks and has good bactierias and critters and stuff in it that will help establish your tank - -i recomend arag-live - - look on drs. foster and smith.com or other supply sites - -i support the 1 lb per gallon rule of thumb myself - - and suggest 40 lbs of sand and 30-40 lbs of rock to start -- -do a long solid cycle and get some good lights and you'll be ready for fish !!!!!!