There is nothing wrong with a coolermaster GX550w Bronze PSU or SilentGold Pro range PSU's, never seen or had one fail on me, the same can be said with Antec or any Seasonic or seasonic component driven unit. EMAC is also reliable.
The OP may have selected that board on costs and availabilty due to geographic locality. If the OP would give us the budget and place of purchase then we can better assist his choice.
i5 2500K has only 4 cores but is very optimized, specially for games. The AMD's 8120 has 8 cores and it will run better when using applications that can handle well these 8 cores. Gamers choose i5 2500K because you don't see games using more than 2-4 cores (maybe this will change in the future). Though, for video editing and other multimedia applications (PS etc.) AMD's 8120 should function better because, in general, such top applications are using more cores than top games.