BaseKit is a web app that generates websites from Photoshop PSD files
There are some nascent attempts, like the cheap-and-cheerful approach of Google Sites, but nothing that comes close to the simple, graceful beauty of BaseKit. For a start, you can import Photoshop PSD files! I can't begin to describe the pains I've been through, as a web designer, trying to implement PSDs in valid HTML and CSS -- but now BaseKit can do it for me, and the code it generates works in all modern browsers. It takes a little getting used to -- you need to name one of your layers 'Header', for example -- but overall, the process is very quick and very smooth. Check out the video on their homepage, if you want to see the PSD import in action.
Even if you don't want to import PSDs, there's lots of other shiny bits to lure you in. The interface is beautiful, like a marriage of everything good about Web 2.0. There is dragging and dropping, resizing, AJAX and widgets up the yin yang -- forms, date pickers, star ratings, imported Flickr and Twitter feeds -- it's all there. If you want to see what's possible, check out their showcase. You'll also notice there's no Flash (but they're working on including it... damn).
If I haven't won you over yet, I've saved the best, beardy-pleasing morsel for last: it generates W3C-compliant code!
Right now you have to sign up for a beta key -- and there are certainly some beta bugs that need ironing out -- but I will try to get some keys to hand out in the next few days over on our Facebook page!