Monospace text (code, tt, or pre tags) has gotten a lot smaller in recent versions of Vector; definitely getting complaints from Firefox and Safari users on Mac, haven't checked other platforms too much yet.
Also affects things like the source diffs in code review:
http://www.mediawiki.org/wiki/Special:Code/MediaWiki/56574?useskin=vector
Version: unspecified
Severity: enhancement
URL: http://en.wikipedia.org/wiki/Wikipedia:Village_pump_%28technical%29#code_and_tt_size