ES34069-BK-180 How Important Is Dual-gigabit LAN For A Super User Home NAS

I'm building my own home server based on Ubuntu with 4 drives in RAID 10. Its primary purpose will be NAS and backup.Would I be making a terrible mistake by building a NAS Server with a single Gigabit NIC?

I know the absolute max I can get out of a single Gigabit port is 125MB/s, and I want this NAS to be able to handle up to 6 computers accessing files simultaneously, with up to two of them streaming video.

With Ubuntu NIC-bonding and the performance of RAID 10, I can theoretically double my throughput and achieve 250MB/s (ok, not really, but it would be faster). The drives have an average read throughput of 83.87MB/s according to Tom's Hardware.

The unit itself will be based on the Chenbro ES34069-BK-180 case. With my current hardware choices, it'll have this motherboard with a Core i3 CPU and 8GB of RAM. Overkill, I know, but this server will be doing other things as well (like transcoding video).Unfortunately, the only Mini-ITX boards I can find with dual-gigabit and 6 SATA ports are Intel Atom-based, and I need more processing power than an Atom has to offer.

I would love to find a board with 6 SATA ports and two Gigabit LAN ports that supports a Core i3 CPU. So far, my search has come up empty. Thus, my dilemma.Should I hold out for such a board, go with an Atom-based solution, or stick with my current single-gigabit configuration?

I know there are consumer NAS units with just one gigabit interface (probably most of them), but I think I will demand a lot more from my server than the average home user.