Parts list for a gaming machine would likely be:
power supply
case
motherboard
2-4 CPU with 2+ cores each
16GB Ram or better
128GB SSD drive for C: (where the OS goes for faster booting)
1TB SATA drive for D: (where the installed apps go) preferably 10K or faster
Windows OS
100M/bit NIC (don't bother with GigE, your ISP isn't even 100Mbit).
Video Card
Sound Card
DVD Rom drive
USB mouse/keyboard
Monitor
I have to disagree with a number of details of your build here.
First, multiple CPU mobos are uncommon outside of server-grade machines. And that's for a good reason: 4, 6, and 8 core processors are easily available at prices cheaper than getting multiple 2 or 4 core processors (once the cost of the more expensive mobo is factored in).
Second, there's no reason to get a 10k RPM hard drive on a $1k gaming rig. All programs should go on the SSD, the HDD should be for data storage only. And for the price (and heat) of a 128GB SDD w/ 10k RPM HDD you could easily afford a 256 GB SSD w/ 4GB 7200 HDD.
Third, unless theatre quality sound is important, there's no need for a separate sound card. Onboard is fine.
If you are building a top end gaming machine from scratch, 2 years from now, exactly what part do you think you are going to upgrade that is going to make the machine better than it is now?
Most people won't want to bother with the hassle, but it's trivial to come up with legitimate reasons for upgrading a system in two years:
RAM. If you have 4 slots available on the mobo, you can spend a little more to get two big sticks now (instead of four smaller sticks), and fill the other two slots when you have more budget.
HDDs. If you put more of your budget into a better SDD for the OS and apps now, you'll get better performance. Get a cheap HDD for other storage now, and add in more storage as needed.
Optical drives. You only need a cheap DVD ROM drive to start playing games. You can easily upgrade to a Blu-ray burner later.
RAID. Add a hardware RAID in with a PCIe slot and external enclosure if you are serious about adding in lots of storage.
Multimedia add ons. Add a video capture card and/or high end audio card to turn your computer into an HTPC.
Second ethernet port. If you have gaming issues because of network performance, it can be helped with a redundant internet connection.