80x24 is the default terminal height. I mostly use this size on all of my projects. It has many favors: compatibility everywhere, tiny bandwidth, etc.
More seriously, I think the 80 column width is just too constraining with more modern languages that aren't remotely as terse as C–not to mention a limit that aggressively militates against in-line commenting. We also have monitors and fonts with resolutions that permit easily reading much denser use of the visual display. I mostly go with 120 chars now (in practice, that means that lines still won't wrap when I print source code files) and however many lines fit into the display pane.
Ime this is true of modern langs like ruby or javascript or Go, as well as older langs like bash. But I know this is a religiously contentious subject, so to each his own.
Anecdotal, but- It does feel like a good visual approximation and when I start to run close to it I usually pause and figure out if that code needs attention.