The following is a general list of supplies and equipment for a freshwater aquarium:
Tank: I prefer either Marineland or Aqueon. You get more tank for your money when you go with a standard rectangular tank. If you go for any oddly shaped tank you will pay more per gallon (hexagon, bow front, column, etc.).
Stand: A wood cabinet stand of the same brand as the tank is ideal. Avoid particle board, you want actual wood so that it is much less likely to suffer water damage.
Glass Top: Again, the same brand as the tank is ideal. The exact dimensions of the inside of the trim on the tanks vary just enough from brand to brand to make it unsafe to assume that the same size glass top from one brand will fit another. Some setups come with a plastic hood that includes a light. This is fine if you are just doing an unplanted freshwater tank. If not then you want to go with a glass top/glass canopy so that you can use whatever light you want.
Lighting: Many tank setups include a light. These are fine for unplanted freshwater tanks. If this is not the case then you need to decide on lighting as a separate issue. I won’t get in to it here because lighting is a major topic in aquariums and deserves its own article.
Substrate: In almost every case I prefer Estes’ Marine Sand which is also known as Ultra Reef and Stoney River. For more information on that please see my article Sand as a (Superior) Substrate.
Heater: My current preference for heaters is the Cobalt Neo-Therm. It is a flat, thermal plastic heater. It has LED lights that indicate the current temperature and set temperature.
Filtration: This is obviously another major topic and the needs vary depending on the tank size, type of fish, etc. Please see the article Filtration for more information.
Thermometer: I prefer either the JW SmartTemp which is a magnetic thermometer (suction cups just wear out) or the Coralife Digital Thermometer.
Air Pump: In my experience every freshwater tank should have an air pump. A nice strong air pump can save and entire setup. If the filter is the only aeration and it stops running for some reason fish can start dying in as little as a couple hours. An air pump alone can keep the entire setup going for a week or more. A strong air pump running a standard air stone is fine. I like the Whisper Air 100 and the JW aircore 1″ air stones.
Decorations: Decorations will vary drastically depending on the type of aquarium you are setting up. You may want a lot of driftwood, rocks, room for plants, or prefer artificial decorations. Whatever you choose I only recommend using decorations that are made for aquarium use. Using items that are not made for aquariums can lead to a lot of major problems and it is best to avoid anything not made for aquarium use.