More and more, I am feeling like the right way to present a graphic novel on the web is to have page 1 or chapter 1 (depending on which is the fundamental Reading Unit of your comic) show up on the front page. Have easy, obvious links to the next reading unit. And have a link somewhere to the latest page, for the people who want to keep up manually.
Smack people in the face with your story’s initial hook, the instant the page loads. Don’t put anything in the way. Don’t dump the 300 pages in and expect them to get hooked.
It’s okay to have the first/latest page(s) be one click away – IF they’ve got big, bright, attractive links that are clearly one of the most important things on the page. Opplopolis (by the same guy behind ‘Nine Planets Without Intelligent Life’, if you remember that) is a good example of that mode.
(If you’re a young artist who’s improved a lot over the course of the comic, this may be a bad idea. I’m mostly considering long-form web comics done by artists who Know Their Stuff.)