Multiple business setup legal/accounting.

We have multiple business operations, all related but currently run seperately under "doing business as" registered names. We are looking at options of changing our operations to protect assets and improve the tax situation. The businesses include a multiple farrier practice, a horse breeding/sales operation, a horse training operation, a riding/horse leasing operation, and an architectural blacksmithing operation.Our thought is to organize in a manner that will protect the assets of each operation should one fall into trouble. In addition we would like to operate so the two primaries are receiving a single large income each rather than mutliple small incomes. My question is what would be the best way to organize these individual operations from both an accounting and legal perspective (i.e. incorporate a holding company and register the individual businesses under the holding company.)