XWikiTips
XWiki is a powerful Java-based programmable wiki system, more of a hybrid wiki/cms. To be honest, in an ideal world I'd rather have continued to custom-implement my site in Lisp, but I had to balance that against time available, and after evaluating several options I ended up going with XWiki for now.
Installation is straightforward on Debian, just following the relevant XWiki docs. The most involved part was setting up "short URLs" - losing the odd javatastic /xwiki/bin/view url prefix - but again, no real issues there.
Syntax Highlighting
XWiki apparently uses Pygments (via Jython) for syntax-highlighting in the {{code}} macro, so the available languages are those supported by Pygments: http://pygments.org/docs/lexers/
Breadcrumb tree menu
Is handled in hierarchy_macros.vm, if you want to change it to display more than 10 entries in the dropdown. https://forum.xwiki.org/t/increase-number-of-entries-in-breadcrumb/903/4