I've decided to give the Hiawatha webserver a try. There are a few reasons for this - I've been using Nginx on this box for the last few months and while it has a much smaller memory footprint than apache apparently Hiawatha has an even smaller one (it is used on embedded systems) and is just as quick serving static content. It also has a very strong focus on security (with built in protection for things like XSS and SQL Injections) and a really clear, easy to understand configuration syntax. Not that I can make use of it on this site as this blog is all plain HTML, but if you're using PHP/Perl/Ruby it has a nice built in fast CGI service tha is very easy to set up.
Anyway we'll see how it goes - it's not like I can't switch back again if needed :-)