Jekyll is a spin-off of a server-side application. Safety features of Liquid templates make sense on the server, but for a desktop application using Liquid is completely pointless. In Webby you are free to do whatever you want with ruby using erb or haml.
Another killer feature is ability to write plugins for Webby in a snap. For example, Webby can process LaTeX snippets and generate formula images for your web page. There is even a gnuplot plugin that lets you plot data that you save alongside your document.
* A nice, easy to configure theme that focuses on readability.
* Built in support for Twitter, Delicious, Disqus Comments, Google Analytics, and Custom Search.
* Rake tasks that make development fast, and deploying easy.
Github repo : http://github.com/imathis/octopress
The only downside as with any static site solution is comments. I currently use Disqus - I have no complaints with them except that I like to own my comments rather than hosting them with a 3rd party.
Are there any opensource alternatives to Disqus? I'd rather run my own comment server then give up control to someone else, if it weren't a pain.
So I grabbed my yak-shaving kit, and rolled my own library in Lua. It's not entirely done, but I'm using it and it may be interesting to you if you like to work with Lua.