Started with a 55 gallon (first real tank). Had as large as a 125. Now I'm back to a 55 gallon in my apartment.
This was all back before the internet really opened peoples eyes to building tanks, DIY, etc. Back then, if you wanted a tank, you had to buy one.
My first project when I buy a house is to build a very large plywood tank with an intergrated plumbing and water change system.