For a killer website, first decide who you want to kill.
Tongue is only partially in-cheek there. It really is important to decide what function or role the website will play in your overall marketing. Certainly it's a place to announce new books and provide links to buying current books. It can be a place for news about appearances and events. It can also be a kind of world reference, a place to read more about the world(s) of your books.
But you should be clear about the role. It should be obvious from the start. Those who write multiple books a year will probably want to focus on releases--wip, cover reveal, sales, actual release, maybe reviews. I get a book written only sporadically, so it would be a mistake to make that the focus. Instead, I treat altearth.net as a kind of resource for further reading.
I can tell you this much: keeping a website (blog, etc) at all up-to-date gets burdensome over time. You can probably get away with simply showing your publications, making links to purchase, and an About Me page, and call it a day.