5 virtual domains, nothing too fancy. No SPAM or AV scanning, but if I
replace the MTA, then those will be added.
I have only really just started looking at a replacement for exim.
Trying hard to not have this degenerate into a "use foo" religious-war
style debate, but why are you changing? (ie, and not upgrading to exim
4.5, which is packaged in debian sarge)