[read_wharf]

"First DO use packages that come with the OS."

I'd go middle ground, and start here, but consider a self-built package where necessary. It depends in part on the focus of your distro.

virtualenv. What problem does it solve? Different python version/environments? Wouldn't that be better solved with another (virtual) server? I understand if an extra $20/month is an issue, but otherwise ...

[read_wharf]

I have just been educated by reading more of this thread. I can see an obvious need for one virtualenv, so that you can separate your service and its needs from the system python and its needs. Beyond that my inclination would be to go more servers rather than more virtualenvs, but circumstances vary and my experience is narrow.

[hynek]

Not every Python application is a big web app. We have systems that run several smaller Python apps. Python is everywhere.