Will the Corsair Dominator DDR3 RAM work with the motherboard?
Will the A90 fit a 10.6 inch video card?
What other parts are necessary for me (exception of the video card in which I plan to temporarily use my HD 4830 and the monitor and speakers)?
Do I have enough USB headers?
In the future if I decide to overclock, is it possible for me?
If I try to OC the CPU, which CPU cooler should I use?
Will the 200mm case fan fit in the A90?
Will the media dashboard be able to control both 200mm fans?
Should I remove any of the peripherals or replace them with something else?
Since I live in Canada, I can use tigerdirect.ca, newegg.ca or other Canadian computer retailers. Please make some suggestions.
Yes the A90 will be able to fit a 10.6" card. Yes the A90 has a space in the front for a second 200mm fan. If the Ultra dash board's fan control is like others then it will use 3pin fan connectors and probably extenders, so if this is the case then you will be able to control both 200mm fans.
The CM Hyper 212 Plus is a good cooler, but at $60 it is overpriced. It will be at a reasonable price at amazon. Or get something else, such as this: Sunbeam Core-Contact Freezer $37 ($11.49 shipping, $15USD rebate).
Sry about skipping the MOST important thing which I thought I added, I plan to use the Phenom II X6 1055T, but I am contemplating on if I should get the Core i5/i7 LGA 1156 or the Phenom II X6. Is the H50 a decent cooler or something if I wish to overclock it from 2.8 to 3.2-3.6?
The Intel system will cost more as the i5-750 is more expensive than the Phenom II X6 1055T, similiarly mobos are better value for money on the AMD side - you get more features for your money on an AMD board compared to an Intel board. AMD will definitely be the best CPU upgrade path, as AM3 is going to be developed for by AMD for awhile longer than 1156. However if a system can last a long time with the same processor then it'd make sense to get the CPU that is most suited to your tasks. So, what are you going to be using this system for?
The Corsair H50 is a decent cooler, altho you can get aircoolers that are just as good at cooling (if not better), while producing less noise and removing whatever risk there is of water leaking. The Prolimatech Megahalems Rev B with the right fan is probably the primary candidate. The fan I usually recommend for it is the Scythe S-Flex 1600RPM, as it has about the highest airflow of the recommend fans on SPCR http://www.silentpcreview.com/article63-page2.html
I just noticed the PSU, you could get a cheaper unit that is still really high quality and modular: Antec Truepower New TP750 $114 ($8.40 shipping)