The worst outage occured today and yesterday all in all the server was inaccessible for around 14 hours out of the last 48 - mails began to bounce and sales screeched to a halt. It was then that we decided to a do a load balancing act.
We already had another server with us that wasn't under heavy load but the problem was with the DNS - not having a residential DNS expert we used the DNS servers of our ISP upto now we switched those across to zoneedit which offers excellent domain names services for a very reasonable fee.
You can easily set up a round robin system and what's more zoneedit can detect when one of the servers are failing and temporarily remove that IP from the list. In other words you get a very simple fail over system for a very very reasonable price.