I tend to agree with the above with one caveat.
Obviously, running a small tank will require more attention to detail. It's harder to keep water quality up. I find a 10 gallon a bit too small for any fish.
I keep two. I have a 20 gallon long for smaller fish and a 40 gallon breeder for larger fish. This tends to work well for me.
I think a 75 would be fine if you're OK spending more on water change and equipment for it. I would also be great for large fish such as larger tangs, angels, triggers, etc.