I never had a asrock either. Im a ASUS, Gigabyte, Msi fan. I never stray on my motherboard brands.
Although i recall way back. Before Dell bought alienware. That alot of alienware builds had Asrocks in them.
Im with that guy. Get a SSD. Id want atleast a 64gb one. For windows install. Plus a few games id jungle around on it. For instance BF3 is like what 21-gb after patches? that 25-gb not going to cut it.
Then whatever is cheaper for a data drive.
Then Id say. Since your getting the "k" version cpu. That youd want an aftermarket cooler for it.
Im a fan of the "sunbeam twister". Make sure it works for your CPU though. Alot of people recommend a coolermaster 212 though. The twister has more features though.
Then Im a fan of full sized towers. One your buying is midsized, it seems. I just prefer the extra room. I never have to worry about "oh will it fit" it fits in mine, or it doesnt fit in anybodies lol.
What games do you play and at what resolution? Are you using this machine only for gaming? if so you might want to get a cheaper cpu like an i3 2100 and spend the money you save on a better gpu like 6870/gtx560.
We need to know your budget before we can help you fully. Regarding the SSD, you don't need to use one as a boot drive...you have a Z68 motherboard, which means it can be set up as a cache drive. Don't get anything bigger than 64GB for this is the cache size limit. However, it's up to you whether you want to set this up or not, of course.
I'd not go with the GTX 550. The 560Ti isn't that much more expensive and performs better. Again, need budget details to help you here.