Gday
tinycrash, Both builds would work, each has good and not so good parts combination. For a gaming build, the i7 CPU is over the top. A i5 3570K will give top performance with the ability to OC should you require it. $$ saved should be used on the best GPU you can afford.
A ATX Mobo will give more room on the board for working, run a little cooler and a Z77 chipset gives you better features.
Providing you are not likely to run Crossfire or SLI, a 600/650 watt PSU is more than you require giving you wiggle room to add things like, 3 screens, more fans, etc.
I usually select low profile RAM, performs the same as ones with fancy heat sinks, but ensures no problems when fitting CPU coolers.
I don't consider the wd10ezrx suitable for a OS drive.
IntelliPower is marketing speak, people think it means a variable speed drive, I have never seen specs for such a drive, I do not think they exist. The drive max speed is 5400 rpm, when it is idle for an undefined time, it comes to a stop, when access is needed again it takes time to come back up to operating speed..Case, Nice, but need to check if it has washable air filters.Below link is a good starting point for a build, can be tweaked up or down a little. let us know what you think.
> http://pcpartpicker.com/au/p/z5Cs
NB. OS is not included.