Four Opterons or 2 Xeon CPUs for Server Build

I'm currently in the process of building a home server which will run a media server, NAS, and virtual machines (among other things). I currently have two options for my CPUs for it, and I am looking for feedback as to what the better option would be.

Option 1: Two E5-2670 Xeon Processors. 16 physical cores and 32 threads. Cost is about $448 with mobo.

Option 2: Four Opteron 6180 Processors. 48 physical cores. Was offered this for about $800 with mobo (which slots 4 CPUs).

I am currently leaning towards option 1 for a couple reasons. First, the 6180s are on the AMD K10 architecture, which is quite old now. So I think each core on the E5-2670 will be much more effective for various tasks. Second, the E5-2670 should (probably) have significantly better single core performance, which will be useful for some of my use cases.

I was looking for additional feedback to see if my decision could be swayed either way. I am no expert at server-grade CPUs, so there are probably things I am missing or do not understand.

For additional information, a high load use case for me on the server I am making would include: streaming HD (1080p) movies over LAN (from NAS), doing file transfers over LAN (NAS), and running 3-5 VMs (all at once).

Thanks.

I went from a double socket 6134 Magny Cours (8 cores/proc) to two Poweredge R710 with dual E5645 (6 cores/proc) each and noticed a fairly large speed increase. I'd suggest going with Intel. If you are interested, there is a rackmount project thread in my signature, which covers all my server stuff from 2009 to present.

Is that much power consumption absolutely required to run a server 24/7 ? I suppose it would be if it were serving 20 different thin clients at once, but for the average home user, me, I'd be looking at fanless setups, ie., no moving parts. I had no idea dual/quad cpu setups used that much power. I would probably only run one if it was dedicated to an intensive tasking project like cad or video production stuff.