I've just switched this site over to Nginx from Apache. The main reason for doing this is Nginx is far better suited to lightweight sites like this as it is especially fast at serving static content while using a lot less ram and seeing as I'm not doing any fancy URL re-writing or other things like that Apache was a bit overkill. The reason I went with Apache in the first place when I first started this site a few years ago was simply it was what I was used to - all the web servers I've configured over the years have been Apache servers so it was all I knew. But since switching jobs about a month back I've been exposed to Nginx and after doing a bit of reading about it have decided that this little Intel Atom box with this very lightly trafficked site would be much happier with something a bit smaller and simpler. My first thought was to go with something like Araneum as it is really tiny and efficient with very few options so securing it is pretty easy. However Araneum isn't in the Debian repositories and the only .deb package available from the Araneum website is for i386 (I'm running amd64 on this box) and I certainly don't want to rely on compiling from source each time the server is updated, so Nginx it is*.
To be honest this site sees so little traffic I could probably run pretty much any web server :-)
* I do like how Araneum provides a Haiku package though - BeOS represent!