Static website generators seem to come and go -- would anyone like to comment on one they like that seems to be lasting the test of time? The obvious one seems to be jekyll (possibly with octopress on top of it), but I'm interested in any others.
Middleman is just simple enough that you can quickly build out an entire website/blog with great functionality, but extensible enough that you can write some custom Ruby to do that one specific thing you want.
I also really like how middleman can essentially use any markdown renderer or template engine. As someone that loves erb, Sass and Rake, Middleman just makes the most sense.
A few sites I've built with middleman
That being said, I'm been using gulp to hack together a system when the site isn't something conventional like a blog, marketing page or docs that many of these generators excel at.
https://middlemanapp.com https://github.com/middleman/middleman
Node.js-based, lots of plugins available via npm, sane themeing syntax. I have a script that generates my site and then pushes it to S3.
My site, such as it is, is available here: https://github.com/drhayes/drhayes.io