First off you will want to get a motherboard that will have room for all of your stuff plus room for expansion. One of the main benefits of building a computer is so you can expand on it later without having to buy an entire new machine so build for tomorrow not today.
- Make sure you have enough SATA ports for you HDD, CD drives etc etc
- Make sure you have enough PCI-e or PCI slots for your tv tuner, wirless cards, video cards etc. (Leave a few open as well for future expansion)
Secondly since you want an intel processor make sure the board supports that as well as the processor type. It will probally be a good idea to match the MB and processor up at time of purchase (even if purchased seperatly).
Third if you plan on hooking up 6 fans make sure the MB can support all of that hardware. Remember it will still need to be able to power other things as well.
Fourthly (is that a word?). Back to the video cards you will want to make sure the board supports CrossFire or SLI as well as the power supply that you are going to match with it. Dont forget you are going to expand in the future so don't use up al your slots.
Fifth: Don't forget about the other components. How much RAM do you want, wil you have USB devices hooked up? Do you want a SD card reader? USB wireless internet? Make sure the board can support your needs. You should make sure everything even the small things are going to have space on the board. you dont want to end up with a board that only supports 8GB of RAM when you want 16 later on.
Finally, your machine looks like its going to be power heavy and sucking a lot of juice with lots of HDD, dual graphics cards 6 fans etc. With this being said a big step is to do your research first. Read reviews and try to find people who have used the board in a similar setup that you are describing. Nothing beats first hand experience.
EDIT in response to comment:
You need to figure out what you want and then what you may want to add in the future.
For example when I first built my machine I had 2 SATA devices (a HDD and a CD-Drive), but I got a board with 5 SATA slots. Since then I have added 1 HDD for space and have room for other stuff, who knows I may come across a free floppy drive
I have yet to need crossfire but I got a board that supported it in case I wanted it eventually. My board has 2 PCI-e slots, which I can crossfire if I want. Once again its something I considered when I got the board (I am still only utilizing 1 of the 2, but I might want a PCI-e/PCI card that does something else other than graphics.
Some other things I looked for in a MB
- On board graphics (In my case I knew I wanted a GPU to handle it all)
- On Board LAN (In my case I wanted this so I wouldn't need an extra slot card to handle it
- Onboard LAN speed, onboard graphics output(HDMI, VGA, DVI), onboard audio, number of USB slots and speed.
- Budget! How could I have forgotten, set a limit and do some hard searching. Who knows what you can dig up.