Uncle picked a great board.
-240 pin DDR3 will work
-DDR3-1866 and DDR3-2133 are oft same price as 1600 so why not take the free upgrade if its available and *if* it's faster
-When choosing speed / CAS use his formula: CAS x 1000/ DDR Speed = nanoseconds
You will find for example that:
DDR3-1866 CAS 9 is 4.82 .... ya might think DDR3-2133 is always faster but at CAS 11 it's not at 5.16 but at CAS 10 it is at 4.69.
-Brand name is hard cause what you see is oft not what you get .... for example Corsair was using Hynix modules initially on their Vengeance Pro line but at some point (IIRC about version 4.51) they switched to a less expensive vendor. Hynix is the "Gold Standard" of memory suppliers.
I find 2400 the sweet spot right now ..... not a huge speed improvement but as long as the system cost increase is smaller than the performance increase, that makes sense to me. Mushkin is my 1st source as I'm guaranteed Hynix in the Redline performance series while with other vendors it can be a crapshoot. Corsair is next .... rarely take anything else unless I can confirm whose modules they using or it's part of a combo deal. Looking at what's on newegg atm...... which one ya want for the same price ?
Mushkin Redline 2400 has 10-12-12-28 timings ($190)
http://www.newegg.com/Product/Product.aspx?Item=N82E16820226417
Corsair Vengeance Pro has 11-13-13-31 ($190)
http://www.newegg.com/Product/Product.aspx?Item=N82E16820233600
GSkill Trident is 10-12-12-31 ($190)
http://www.newegg.com/Product/Product.aspx?Item=N82E16820231589
Looking at your situation.....and 2 x 4 GB
Gskill / Corsair DDr3-1600 CAS 9 is $80
http://www.newegg.com/Product/Product.aspx?Item=N82E16820231314
http://www.newegg.com/Product/Product.aspx?Item=N82E16820145324
These Corsairs are $75 w/ promo code but may hit ya aftermarket CPU cooler if used.
http://www.newegg.com/Product/Product.aspx?Item=N82E16820145345
Mushkin and Corsair Vengeance are up at $85-86
http://www.newegg.com/Product/Product.aspx?Item=N82E16820226395
http://www.newegg.com/Product/Product.aspx?Item=N82E16820233379
At 1866 CAS 9...
Gskills are $83 @ CAS 9 (and $85 at CAS 8)
http://www.newegg.com/Product/Product.aspx?Item=N82E16820231455
http://www.newegg.com/Product/Product.aspx?Item=N82E16820231538
Mushkin and Corsair Vengeance are at $87 and $88 .... $2 more than 1600
http://www.newegg.com/Product/Product.aspx?Item=N82E16820226302
http://www.newegg.com/Product/Product.aspx?Item=N82E16820233240
At 2133 CAS 10 ....
Gskills are $71 w/ coupon code
http://www.newegg.com/Product/Product.aspx?Item=N82E16820231654
Mushkins go up to $95 this week
http://www.newegg.com/Product/Product.aspx?Item=N82E16820226200
Corsairs at CAS 9 are $103
The GSkills are the lowest price choice available across all three speeds if ya coupon eligible. The price on the CAS 9 2133's tho as even tho $15 more than their 1866 stuff, it's still is attractive. But again, the Mushkin 2400s at CAS 10 w/ $90 price tag is a very good deal w/ guaranteed Hynix memory so going higher is certainly something worth pursuing.
http://www.newegg.com/Product/Product.aspx?Item=N82E16820226345
The GSkill 2400 CAS 10 is $5 cheaper but again slightly slower timings at 10-12-12-31
So...with the DDR3-1600's at $80 for the lowest price modules and just $85-90 for the DDR3-2400, springing for the extra $5 for the Gskill 2400s seems hard to argue against .... tho personally I'd go the the Mushkins for the better timings and security of getting Hynix modules .