I had goldfish when I was a kid. They did not end up well because I was clueless on fish care.
My serious fish keeping record started after I graduated from the college. I spent over two months doing research online on the subject of how to get started as well as various other subjects on beginner fish keeping.
The extensive research did pay off. I successfully started my tropical planted aquarium as you can see in my sig. Right now I keep only tropical fish. Dwarf Gourami, German Blue Ram, Cardinal Tetra, Black Phantom Tetra, Rasboras, corydoras, Neon Rainbow fish, etc.
Topical fish are in fact easier to keep than goldfish because they require smaller tank due to lower bio-load. Goldfish are messy and they produce a lot of ammonia. You need extra large fish tank and heavy duty filtration for goldfish. For the same tank, you can have a lot of tropical fish but only a few goldfish. I obviously love to have more fish to look at.
Yes, you need an aquarium heater for the tropical fish but it's cheap to get one and there is really nothing complex about it aside you must be more careful on the temperature of the new water each time you do partial water change. Tropical fish are more vulnerable to temperature shock.
Aside the tropical fish, I have zebra nerite snails, assassin snails, as well as yellow shrimps and red cherry shrimps in my fish tanks.