Is your Leopard Gecko going to be a juvenile or an adult? You can keep a juvenile in a 10 gallon terrarium for now as that should be a sufficient place for him to live. However, as he matures and gets older, usually around 18 months or a year, I would purchase him a 20 gallon long tank as he will likely reach a decent 8-10 inches and a 10 gallon is just too small for him. That's what I personally did with spotty. At first it was a ten gallon tank but later at around his age of 18 months, I bought him a larger terrarium and I can tell he seems much more happy now. He was showing the clear signs of boredom. For instance, he would scratch his glass tank and try to climb out by clinging on to the silicone which holds the glass. He also did not climb a lot of other things he had. He stayed in one place all the time and was EXTREMELY lethargic. At first I thought he was sick, but later it turned it he was just very bored. Once I had bought him the 20 gallon long tank, he was much more happy, climbed his toys, was not lethargic and explored a lot. As for the other items on the supply list, the substrate is perfect as it very much decreases the likelihood of him becoming impacted and is brown, which kind of mimics their natural environment. As for the hides, I would either purchase three hides, or purchase two but put a large log or something like that in the center of his tank which may serve as a hide as long as he can slip beneath it. Please do not make your cold/ moist hide the same hideout as this very much increases the chance of him catching a virus, becoming lethargic, and having upper respiratory infection. Please make your moist hide warm. You will need a: warm dry hide, warm moist hide- with moss or wet paper towel, and finally a cool dry hide. When I first purchased Spotty, I did the same mistake as making the cold hide moist. He later become very lethargic and would not leave a hide for up to 2 weeks at a time. So, I posted a thread about that and a few members replied to make his warm hide the moist hide. That's exactly what I did. He is no longer lethargic, doesn't stay in one hide no longer than a day, explores his tank much and seems much happier. What people USUALLY, not all, do is place the warm/ moist hide on the left, the warm dry hide in the center and the cool dry hide on the right. Many also place their water dish on the left side but I don't. The UTH should be sufficient for a 10 gallon but not for a 20 gallon. For a 20 gallon, you will need the 30-40 gallon tank UTH. The thermometer is good as it is digital and reads more accurate readings. However, you will need to check the ambient temperature for both sides of the tank so you will need another digital thermometer by Zoo Med. The water dish seems a tad too small. Do they have a medium one you could purchase? A thermostat I personally use is:
http://www.amazon.com/gp/aw/d/B000N...r+reptiles&dpPl=1&dpID=41aKd0vxIfL&ref=plSrch
I've been using it for a while and it's pretty good. Also, what are you going to feed your Leopard Gecko?. If you haven't decided yet, I recommend either crickets or dubai roaches. They are both high in protein and calcium value. Have you read about how to gut load crickets? If you haven't, gut loading is the process of offering your feed food which is rich in protein fiber calcium and vitamins. You usually gut load a cricket or roach one to two days before feeding. The best things for gutloading can be- carrots, egg shells, apples, oranges and lemons. For crickets, you can buy commercial cricket food by Fluker's, which is what I do, but in addition also offer the crickets some fruits and vegetables. This will ensure your crickets are gut loaded the best. This also applies to roaches but they may require different feed. Have you purchased the calcium and multivitamin powders? If not, in order to ensure great health in your animal, you must powder their prey with calcium and multivitamin powders. You should leave a small dish, or a bottle cap well rinsed, inside the tank at all times filled with plain calcium with NO vitamin D3. You would also powder your animals prey with calcium WITH vitamin D3. For a juvenile you should do this twice a week and for an adult once a week. Then, you would powder the feed with multivitamins once a week no matter how old. Here are links to the best calciums and multivitamins:
Calcium WITHOUT D3-
http://www.amazon.com/gp/aw/d/B00BS...ds=rep+cal&dpPl=1&dpID=51vCIEsVPRL&ref=plSrch
Calcium WITH D3-
http://www.amazon.com/gp/aw/d/B0006...ds=rep+cal&dpPl=1&dpID=51laxe70z+L&ref=plSrch
Multivitamins-
http://www.amazon.com/gp/aw/d/B0007...ds=rep+cal&dpPl=1&dpID=51QwFQuFZ1L&ref=plSrch
Are you planning to also add some furnishings into the tank? As I said before, Leopard Geckos get bored fast and need plenty of items to have "fun". Consider buying a reptile hammock, some artificial plants, or wooden decor. That's it! Good luck with your Leopard Gecko.