We use Intel Xeon Quad core servers with a minimum of 4GB RAM memory and 100Mbit/s connectivity. All servers have a minimum of 4 drives configured in RAID10 format and hardware raid controllers for maximum reliability. That means our server will remain functioning even if 2 drives fail at the same time (1 drive from each raid1 sub-array in the RAID10 array). That also means you will not lose data. This configuration provides a lot of power for your web sites which insures they will open quickly at all times.
Additionally, all services on each of our servers are being monitored every minute and we are alerted if a service goes down so we fix it immediately. We always understand first if there is a problem with any service on any of our servers. That gives you assurance your server is taken care of and you can sleep at night knowing your web site is at good hands.