It really depends on so many things.. Salt or fresh? Do you want to maintain yourself? Salt water tanks are a lot more fun to have but more expensive and A LOT more work. I have a small fresh water tank I barely touch, cool little fish, a catfish etc..and salt water tank.
In the Salt tank I have a stingray, a puffer, a Wrasse, a Tang, and a Lion Fish
Here is mine Salk water tank and some of the fish..
