S Corporation and C Corporation
Both S and C corporations have a lot more requirements involved than an LLC. Both of these entities must elect board of directors and hold annual meetings, sell stock shares to raise capital, fill out IRS Form 1120, and have shareholders who elect managers to run the day-to-day business. The shareholders are not held liable if an S or C Corp goes out of business. A C Corporation must also deal with taxation at the corporate rate and double taxation and no pass through tax treatment.
Limited Liability Company (LLC)
Limited Liability Companies are easier to set up with the state and easier to run. Their members have no personal liability and can set up a management structure however they choose. The income is passed through to the members and they cannot sell stock but can sell interests in the company to raise capital.
LLC's are available for smaller businesses and entities that do not want to be held liable for the business decisions of its members. S Corps and C Corps are for larger companies that go across state or international lines and do business on a grander scale. A person needs to decide what kind of company they are going to be before they decide what type of set up to choose.