While I use the Debian Server rather than the Ubuntu version, my setup is pretty much identical. I use EHCP and just apt-get it to the server letting it set itself up. Once it's set up I tweak a few settings for security reasons. I'm running 5 sites from mine at present on a standard residential 10MB connection with very little speed issues. I've got members connecting to my sites from around the world and no one has complained about slow page loads or connections thus far. (I also just recently see more added a free cloud/security service for all of my sites which greatly reduces the bandwidth required to serve up pages since all static content is now cached on their cloud servers.)