Join Date: Jul 2010
Location: Outside Philadelphia, PA
Yes, a 500 gal tank would be great for a "small starter system"! (grin)
The size you choose is going to depend upon a lot of things. IMO there is no one best size, or one size that fits all.
I would first figure out what sort of livestock, both plants and fish that I wanted to keep, and then choose the tank and the rest of the equipment to accommodate them. Of course, this process also stops you from getting something that would be out of the question for you. For example if you want adult discus you are gong to need a large tank. If you can't afford that you need to find something else to keep.
Then figure the total cost of ownership, not just the initial purchase, but what it will take to keep it going. Your going to need to replace light bulbs, pay for electricity, replace CO2 stuff, fish food, test kits and so on.
If you feel you can afford it all then go for it, if not either scale it back or forget about it.