I would highly reccomend not get a saltwater setup, since it requires a lot of knowlege about fish and water chemistry. If you are now asking what is the next step, I would reccomend for now freshwater tropical community fish. Here is what I started with years ago. 5 neon tetras, 5 tiger barbs, 3 cory cats, 5 ottocinclus. This set up should be just fine. However you will need to cycle you tank, I would probably get 3 young barbs and cycle it for a week or two make sure the water is stable (no ammonia) then add 2 more. Give it another week or two then add cories and last the neons and the ottos. That setup should work very well with your aquarium.
Now equipment: I prefer 2 filters, one on either side of the tank, a 150-200 watt heater. Good Luck!
