HDD spindle speed for NAS and Streaming

Hi All,

I am soon gonna buy a new NAS. I was looking at HDD for the NAS and read good things about the new WD Red drives. They are built for a NAS environment specifically. However, the RPM is around 5000 for these. Since my NAS is also my Plex media server and needs to stream at least 1-2 HD 1080i60 video streams (roughly 10 MB/sec each ) and stream music to the sonos devices, I was worried about the ability of the drive to perform.

Synology rates most fo there NAS devices at serving 180MB+ with dual wired gigabit cables. So I did not want the drives to stop me from getting the data transfer I need, but did not want to spend money on enterprise level drives.

What do you guys recommend?