Re: in normal use, the load average is around 1.1.
I could probably bring it down a little with some tweaking - for instance, the screenshot shows a lot of Perl running, which is the various Amavisd-new child processes. Tweaking that down, and also the maximum number of simultaneous SMTP connections allowed would probably get it a lot lower.
Normally, I also have a couple of IMAP clients signed in continuously. And clamd is a bit of a hog too, at times. So, yes, I could tweak this down - but 1.1 on a system with two cores is perfectly livable with, and not really in the region where I need to worry about tinkering.