You don't need 16gb at most 8gb is still overkill. You also need dual channel not quad channel ram as it isn't support by your motherboard, you also need to confirm that the ram will fit with that cooler as most need smaller heatsinks to fit.
that heatsink will take up RAM slots... and its not that good anyway. Get the Hyper 212 for $30, its small but cools as well as the big ones.
Just because u have 4 sticks of RAM, doesn't mean it's quad channel. Shadow is wrong there... You have two seperate ram channels that are each Dual. Most motherboards will color code them... so you will have 2 whites and 2 blues. If you have 2 sticks, you use just the whites. if you have 4 sticks, use all 4. no problems.... still all runs at DDR3 1600 speed.
*I have the x-540 speakers... for $99 they are phenominal. highly recomended
Neither of those sound cards are better. Do any of them offer anything that you want over what your onboard ALC892 does? That should offer a noise floor below human hearing and unnoticeable THD. (read: the sound quality should be unnoticeable different). It also gives 7.1, so unless you need some specific feature of one of those sound cards, your onboard is probably good enough.
Hard Drives: You probably don't need the velociraptors AND the SSD AND the Spinpoints. Personally I don't think SSDs are worth it, but if you want one to boot off of and have some applications on, go for it. However, having Velociraptors AND the spinpoints seems a bit redundant. Just get a couple more spinpoints. If you really need some speed for scratch space, RAID 0 them. Or for $500 you could get another/some more SSDs for scratch space. That should be enough space and give substantially higher performance. If this isn't what the velociraptors were for, then I'm sorry, I don't understand.
For monitors, If you want professional color quality, get yourself some IPS monitors. These will far more accurately represent color. I know there are the Dell Ultrasharp series, and there are more, I just can't think of them atm. These'll run you a few more $$, but I think you can squeeze out the savings from not getting a sound card, not getting Velociraptors.
Also, that's mighty expensive for a case. The ram should work fine, as long as it fits. I have no experience with that heatsink to make recommendations.
Sorry bout the RAM thing (lowrider) only realised after I posted that A quad kit is nothing more than two matching pairs of dual channel memory. It mentioned it in the details of the chip.
On the monitors this as Scotu said IPS is propably the best fpor you since gaming will be secondary the u2410 and u2711 are excellent IPS monitors with good viewing angles better color representation ect.