You don't have the budget to watercool, and honestly unless you are really OCing your CPU and GPUs, you don't need it.
I would stick with the 2 8GB Dimms, this way if you ever need/want more, you have a little more flexibility.
Unless you are going for super high overclocks, don't waste your money on the Maximus V, that AsRock will work great.
A sound card is personal preference, if you have nice headphones or speakers, you will want some kind of sound card to eliminate interference from your system.
As Jed mentioned, there can be clearance issues with RAM, try the Corsair LP series, they will fit underneath.
Microstuttering is an issue with more multi-GPU setups, and there is also compatibility and driver issues. I personally would rather get one GPU. If you are only gaming at 1080P, then one HD7970 will be plenty. Moving up to 2560x1440, I would take a look at the Titan. Just be aware the new nVidia 7XX series GPUs are due out soon, so prices will likely change.
You don't want to fill up SSDs too much or they lose performance, I would keep the HDD.