If my commercial experience is typical, $1,000,000 worth of general liability insurance is a good starting point. On my latest renewal I discovered that raising my limit to $2,000,000 did not increase my premium. Ask your agent for quotes on both coverage limits.
The more assets you have, the more important liability coverage is and the more coverage you need. Please consult your insurance agent for all of the facts. You will also want to get a full explanation of manifestation or sunset clauses when choosing your policy.