preface: i'm not an expert and i've not started any companies.
you incorporate in delaware because it has, by far, the most robust and established corporate laws and legal system.
you go with c-corp because they're the easiest entity to run with established legislation with respect to selling interests and tacking on investors. if you want to get funding and stuff, c-corp is the way to go. from what i've seen, you "can" do it with an LLC, but the laws and protections and precedents aren't really established for that route yet, and most VCs want something safe and inexpensive.
you incorporate in delaware because it has, by far, the most robust and established corporate laws and legal system.
you go with c-corp because they're the easiest entity to run with established legislation with respect to selling interests and tacking on investors. if you want to get funding and stuff, c-corp is the way to go. from what i've seen, you "can" do it with an LLC, but the laws and protections and precedents aren't really established for that route yet, and most VCs want something safe and inexpensive.