I’m running a server with Windows Home Server 2011. I’m also running PLEX on it to use it as a media server. I need to add more storage space to it & am not sure which WD drive is going to fit my needs best without being too expensive. Any ideas? Will a green work? How about a red/NAS? Would an A/V be best for my application? Too many choices… 
You might be interested on the WD Red and WD RE line of internal hard drive. Check the links below for more inforamtionl.
