We have been using a 2008 iMac (upgraded 2 TB) hard drive as the media server for our iPads, Iphones, and ATVs. It runs 24/7 - has worked great and had no issues. We running out of room on the internal drive and are considering buying an external drive connected to the iMac via firewire. I also briefly looked at the NAS route and decided it wasnt for us. The external drive would only be used for our iTunes library only. Are there any issues with sleep/wake and external drive? Is there any lag time compared with media store on an internal drive? The iMac is in our kitchen so noise could be a factor. Any other input or suggestions on implementing would be greatly appreciated.