First, Reptiles are normally horrible investments, most of us lose money, but if you want to roll the dice. Investments are about what the market as a majority likes. What you enjoy might not be a good investment tho. I love deserts and would no doubt enjoy producing combos with them... I doubt your going to find anyone arguing they are a good investment. I wouldn't enjoy trying to move the offspring.

As far as dom/co-dom, personally I think banana is a good investment after the market finally got realistic with them. It is a morph most still want and super bananas are in demand. I also think leopards and orange dreams will have high demand for years to come. But, all I am doing is guessing.