SBCL with hunchentoot. My colleague started work on a side project in this stack and now we are trying to make it into a proper production application within our organization. I am climbing some learning curves at the same time, emacs, lisp, several packages... Fun times!!!
Came here to see if this was mentioned. My choice, too. Absolutely cannot be beaten, imo. I've written my own framework on top of it for things like simplified routing and static page compilation with automatic sitemap generation.
Editing the live image is awesome though and the flexibility... Definitely makes me want to explore this space more.