You're right. Memory won't play too much contributing to performance. There is no performance increase in gaming for speed or amounts over 8GB. There is a small increase in benching. you would have to OC the memory probably to 2600 to see any gaming performance and it will be small. This may or may not change with Haswell.
Everyone has their favorite brands. I went with the Samsung green memory. OC's well and if it doesn't I'm not out of a lot of money for price vs performance. I usually stick with mushkin. Gskill makes good memory but personally I don't like their ethics to over saturate their product line with similar memory variants. I think I buy my parts based on company like a stock broker.
What it will play a role in is very intensive programs or VMware. I would build your loop based on future upgrades. A good 360 rad will cool your processor and gpu with some overclocking headroom. There are a few reviews on this. Also it will give you a chance to test the cooling capacity of the single radiator if you decide to upgrade to Xfire and plan your loop from there so you don't over spend. Especially when it comes to tuning it out and finding out if you need to change fans.
The pump is one thing I wouldn't skimp on. If you get quality it will allow you to expand your loop and also impacts pump life. If you are on a strict budget I would get the xspc 750 v4. It seems xspc cares about this product to be constantly trying to improve it. The older version have a bad rap. I personally used this pump in the past without a problem.
You may already know all this just putting it out there.Edited by stansfield - 11/23/12 at 6:48am