I built my first computer a little over two years ago as i needed an upgrade from my aging Pentium 4 system that was nearing 10 years old. Like many I was a little hesitant to make the plunge but after watching videos and reading a bit i decided to do it, and very happy i did. The two main things i got out of it were a great computer at a fraction of the cost and an increased knowledge base to help with future upgrades and troubleshooting. Its all pretty much "Plug and play"
My system is pretty quite i've added an 80mm fan to the front of the case to help move air and a 500w PSU which blows air out the back. The two fans are pretty quiet the only time i hear the HTPC is when i boot it up and the HDD spools up. It depends a little on how close you will be to the case as far as sound goes but the build i listed is quiet.
I checked biostars website and although i didn't see your ram listed it does support certain sticks of corsair ram. I may be wrong and please be diligent and chk, I doubt they have the time to test every configuration of ram with each mb. I've never had a problem using ram that wasn't on the approved list. Your ram is DDR3 I'd imagine it would be find...and ram is pretty cheap these days anyway.
There are tons of options out there the build you listed would work but its a little more dated with DDR2 ram (you have DDR3).
Also the chip i listed has the opportunity to be unlocked to a quad core (The MB supports this feature). Its a gamble though mine unlocked to a triple core as the fourth core was not stable. Its also a black edition chip which means you can overclock it easily with just a multiplier bump. Not that you would need to for an HTPC but if it did unlock and was stable it would prolong the life of your system as software become more multithreaded. Would also double as a solid "backup" computer
This build would be nearly half the size, but not have the potential to unlock cores
http://www.newegg.com/Product/Product.aspx?Item=N82E16827135204 $20
http://www.newegg.com/Product/Product.aspx?Item=N82E16811154091 $40 Free shipping Promo EMCJKJB24
http://www.newegg.com/Product/Product.aspx?Item=N82E16811154091 $90
http://www.newegg.com/Product/Product.aspx?Item=N82E16819103951 $100 New APU with graphics on CPU
http://www.newegg.com/Product/Product.aspx?Item=N82E16820220580 $65 - $25 MIR Only 32gb enough for OS
Shipping $10 +/-
Total $ 300 +/-
Much smaller form factor, triple core APU, SSD for much faster boot time and no noise. Your memory should work with this MB but verify. I've had my HTPC for two years now and use it as a back up computer when needed so the larger case works well for me. If I was building another solely as an HTPC i'd probably go with something smaller like this to fit in with my surround sound reciever in my media center and keep temps cool.
http://www.newegg.com/Product/Product.aspx?Item=N82E16822148698 this is the HDD i used but its sold out.
Depending on how many programs you plan to run the SSD may not be a good option as it may not be large enough. But if your just going to have your OS and a few other programs it would work. You could always add an HDD down the road for music, movies etc.
I picked up a wireless keyboard and mouse for 20$ and it works great.
Wow i got a little long winded lol.