The most popular form of business entity today is the limited liability company (LLC). Like a corporation, it offers personal liability protection for its owners. But for income tax purposes, it is treated like a sole proprietorship if there is one owner or like a partnership if there are two or more owners (the LLC can opt for C or S Corporate tax treatment but this is seldom done).
The S corporation is another popular entity choice, offering personal liability protection and pass-through income tax treatment for owners.