Hmm, how do I say this without sounding shameless? I just launched Capturely (http://www.capturely.com) to help people, especially web designers, make Coming Soon pages. It takes care of all the backend stuff for you. I'll stop there, though, before this starts to sound like an ad.

From all the Coming Soon pages that I've looked at (quite a few, lately), they all have the headline, short description and an email form. It's far from real data, but hey, that's how pretty much everyone else does it. I'd be curious to run some real tests though, which, hopefully, Capturely will let me do.