I'm using Amy and Emma mostly (Amy as my VA text to speech voice and Emma as my EDDI voice) and bought them here:
http://www.deskshare.com/text-to-speech-voices.aspx
I also have several HCS voicepacks and you can integrate EDDI in them individually. I'm using the Multi-crew profile (used to be a free profile but now comes with the Astra voicepack)
With this Multi-crew profile you can use different voicepacks at the same time so you could assign Orion to Comms, Vega to Flight and Eli to Tactical.
Multi-crew has an option to turn EDDI on or off and comes with predefined commands that make use of EDDI.
The advantage of using Multi-crew is you only have to modify one profile if you want to make personal changes to EDDI and still use the different voices that come with the voicepacks.
More info about Multi-crew is here:
http://forum.hcsvoicepacks.com/forum/elite-dangerous-discussion/6398-multi-crew-profile