The real question here is "Do you believe that you will be in a position to have a steady revenue stream and a clientele base that would require Liability Insurance?"
$1M is very standard for liability policies. My "pay the bills" job has me dealing with professionals that are required to carry at least a $250,000 individual / $1M aggregate personal liability policy. It's a very standard amount across many industries.
I'd like to hear what sort of business you intend to operate, what kind of risk you foresee, and the environment you plan to operate before making a judgement call on if you need liability insurance at all. If your business is dealing with the public in a high profile way where you are being hired to render a service, like a wedding photographer, then insurance is almost a "must-have". If you are shooting wildlife on state grounds then I'd probably give you a different answer.
Personally I do not carry liability insurance but my situation maybe very different then yours. I'm very much a semi-ish pro, mostly shoot for fun but occasionally make "beer money" now and then. My greatest risk is I shoot very expensive cars for an organizer / owner where I'm acting as a 3rd party. Theoretically I could have some type of crazy mishap and damage a million dollar car but I'm shooting for either the owner or the event and would be covered by the insurance carried by the 1st or 2nd party. That said, I know I risk the ire of an owner and the organizers if something stupid happened but I do not feel that Liability Insurance is need nor do the organizer require me to carry it.
...see how complex the issue can get?...