Well first we would need to know what your plans are for the tank. Do you plan a Fish Only, or a Reef set up?
The equipment will work for both and alot of this is basic.
RO/DI unit - For your water, you can get at Fish store, but you are taking a chance. You don't know when the last time they changed their filters. By the time you are done, you will have several thousands of dollars envested in your tank, You really shouldn't chance your livestock on did the guy at the store change the filters out this month. Plus it is alot more convienant to just have a system at home.
LIVE ROCK- Recommend 1 to 1.5 pounds per gallon of the tank. tank is 110 so you need 110 - 165 pound of live rock.
LIVE SAND- Recommend 1 to 1.5 pounds per gallon of the tank. tank is 110 so you need 110 - 165 pounds of sand.
You can save alot of money by buying some base rock and bagged sand, (not live) get about 80% not live, then get the rest live. Over time the life of the live rock and live sand will spead to populate the non live. So in a few months EVERYTHING will be live.
Hydrometer or Refragmenter- this is use to check the salinity level in the tank. The hydrometer is a plastic square with a swing bar, this is usally about $10buck. But I would recommend just getting the refragmenter. It is 100x's more acurate. They are easy to use and don't cost a whole lot. about $40bucks.
POWERHEAD - I would suggest two if the tank is 75gallons and under, and three if the tank is over 75gallons. So for your 110 I would suggest three. Think about 3 maxi jet 1200 or Seio 1100, Tunze's, There are a couple of very new powerhead on the market. So just check around, look at reviews to the different powerheads, see how people liked them.
SUMP OR SUMP/FUGE-The sump or sump fuge is a tank under the tank. This is where you will keep most of your equipment. This is also where you will filter your water. There are a 100 different ways to set this up. and people keep different stuff in it. Basically you will have:
PROTIEN SKIMMER- Get a skimmer that is well over rated for your tank size. The companies do have a habit of over rating their skimmers, Also alot of times they don't take into consideration if the tank is heavyly stocked. On you 110 I would look into a AGM G-3, Corallife Super Skimmer or something simular.
HEATERS- I would get two heaters, I would place one in the middle area of the sump, and one in the return, If one goes out, you would still have the other to cover the tank.
FUGE AREA- This is where is varies a bit.. But for the most part you will want to keep some live rock, can be part of the total from above (100 in tank, 65 in sump) some macro agle, a small light for the top of this area.
RETURN PUMP- this is just as it says, return the water from the sump area back up to the tank.
ODD & END THINGS YOU WILL NEED- There are a few other things needed.
GFI OUTLES- Replace the regular outlets with the GFI outlets, this is a SAFETY measure.
EXTENSION CORDS- look for "SURGE PROTECTION" on what ever cords you do get. I would recomment looking for "SHOCK BUSTER" brand, you can usally find these at Home Depot, Lowes etc.
TEST KITS- to start off you would only need a test kit that test, Amonia, Nitrite, Nitrate and PH.
You can easily find test kits that cover all of these. After you get the tank running for a while and are ready to add livestock check into other test like Calcuim, ALK, Phosphate and others.
LIGHTING- There are many choices for lighting, I will tell you more about the choices when we know what type of tank you are planning.
There are probley some items I have missed, and other will tell you. This is just the basics to get you started.