*facepalm*
faster ram give you overall faster system, not just about emulation. considering the price, might as well get quality ram that have certification for XMP 1600MHz
GPU, not so much for emulation-centric PC. even mediocre $100 discrete GPU is more than enough for dolphin (or pcsx2 for that matter)
with P67 board, you can overclock :p
beside, if you're setting on discrete GPU, why bother with H67 at all, the main difference H67 and p67 are intel IGP and overclock feature (even if you're not using it, the option is there)
even with non K series sandy bridge you'll still be able to add 4 cpu bin to turbo boost ration, with H67 board, not a chance
i7 2600 stock clock is 3.4GHz, with default turbo ratio for 1 core active is 3.9GHz. with p67 board you can add +4bin to make turbo boost ratio into 4.3GHz when single core is active.
hyperthreading won't add benefit for emulation in dolphin. that's why better to get 2500K (seriously, almost $100 difference), OC that into 4.4GHz with ease on ALL 4 core.
(even for OC newb, just choose auto from bios/EFI, for advance OC'er can get better result from manual setting).
rather than getting 17 2600 (non K series) + H67 mobo, getting i5 2500K + premium P67 is even cheaper.
your post add those i7 2600 + H67 @
$398
my i5 2500K + P67 board cost me LESS than that, but when OC'ed gonna leave that 2600 in the dust if we're talking about performance

i5 2500K = $219
http://www.newegg.com/Product/Product.aspx?Item=N82E16819115072
my asrock p67 extreme 4 = $159
http://www.newegg.com/Product/Product.aspx?Item=N82E16813157229
total =
$378
you can use that extra $20 to get better ram, or cpu cooler.
*asus p8p67 is even cheaper on newegg, $155 or $139 after rebate
http://www.newegg.com/Product/Product.aspx?Item=N82E16813131705
even if you don't plan on OC, getting p67 board still a better option just in case you're interresting on OC in the future or for getting better CPU later on. it easier to resell cpu that mobo

if you're really on tight budget you really need to sort your component priority to get the most out of your system and balance the overall component you choose.
even when not planning on OC, i'd still reccommend 2500K/2500, and use the money for better overall component.
it's no use getting best componen only on 1 or 2 area and left the other with minimum care