Each U.S. state has laws that allow you to form an LLC. Similarly, each state has its own rules governing the formation, governance and management of LLCs. Delaware LLCs have the benefit of being simple to form, extremely flexible (with few restrictions on management and governance arrangements), and more familiar to parties you will interact with. In addition, the process of converting a Delaware LLC to a Delaware corporation, should you ever decide to do so, is straightforward and common enough that there are standard forms addressing most elements of the process.
LLCs will not typically pay corporate income tax anywhere; they're a pass-through entity. Establishing a Delaware LLC will not, by itself, obligate a person to file a personal income tax return in Delaware.
This! Delaware is simply the choice for most because of conventions, marketing, and (legal) history. The ideal choice should be Wyoming in my humble opinion.
Unless you live in Wyoming or Nevada, you plan on raising VC money[1], or you know that you will be having substantial business operations in multiple states, you should generally incorporate an LLC in the state in which your primary business operations will take place.
[1] Most VCs require C-Corps. A few enlightened VCs will invest in LLCs, recognizing the tremendous tax benefits of the LLC form. In either case, they will require the entity be formed in Delaware due to its business law history.
If the annual renewal cost of your business entity is a dominating factor of where you're going to site the entity, you should probably be thinking strongly about whether you should be forming an entity at all.
Each U.S. state has laws that allow you to form an LLC. Similarly, each state has its own rules governing the formation, governance and management of LLCs. Delaware LLCs have the benefit of being simple to form, extremely flexible (with few restrictions on management and governance arrangements), and more familiar to parties you will interact with. In addition, the process of converting a Delaware LLC to a Delaware corporation, should you ever decide to do so, is straightforward and common enough that there are standard forms addressing most elements of the process.
LLCs will not typically pay corporate income tax anywhere; they're a pass-through entity. Establishing a Delaware LLC will not, by itself, obligate a person to file a personal income tax return in Delaware.