There is no single answer to this question, as it depends on a number of circumstances:
First, is everyone putting in money and receiving equity (ownership) in proportion to their monetary investment? Or are some investors contributing either in kind (e.g. property, such as intellectual property) or sweat equity (i.e. being given ownership in exchange for their work or effort). If some of the investments are non-monetary, then a limited liability company (LLC) is probably a better choice. It is easier to award or grant ownership in return for non-monetary contributions with a limited liability company than a corporation.
Second, and probably most importantly: is there a hope or expectation that the business will one day be able to go public. If so, it should be created as a corporation—since an LLC can’t go public. Public offerings are something corporations do. If a business is created as an LLC and later the owners want to go public, they’d have to first establish a corporation which would take over all the assets etc. of the LLC. It’s easier to set it up as a corporation from the beginning if the business’s creators are planning a public event from the outset.
Third, and related to the above: it’s generally a little easier to transfer the stock of a corporation than membership in an LLC. If you anticipate having or wanting to take multiple people in as investors over a period of time, it’s probably a bit easier with a corporate structure.
Fourth, in a similar vein, if you expect to have employees and reward them with equity or ownership at some point, it’s again probably easier to do this with a corporation.
In general, an LLC gives you more flexibility in how you value different types of contributions, and is a good business structure to use if there’s a distinction between the “money men” who put in cash and the work-a-day owners, and the work-a-day owners want to own more than their monetary contribution would normally grant them. The corporate form, by way of contrast, makes it easy to grant or transfer ownership at subsequent dates. At the end of the day, most of what can be done with one can be done with the other (other than going public), so you should consult with a business attorney who can evaluate all your needs and expectations and recommend the best structure for your situation.