global environment variables?

[nemo@cheeky.house.cx]

I'll get to the point:

My system is behind a proxy at my ISP... everything I run that can use
a proxy recognises http_proxy and ftp_proxy environment variables. 
(apt-get, wget, lynx, etc)

So it seems logical to only need to set this in one place, right?

Where would that place be?

I tried /etc/environment - and that works for my login shells (bash
as root, zsh as user) ... but isn't seen from scripts run from cron. 

Is there any recommended way to make a an environment truly global?
Is there something I've missed?

.../Nemo