Is this a good pc build?

yes and phenom 2 x6 is bettter than i5 2500k for gaming and look at the price man for $200 you are getting a 6core processor your cpu cooler is enough for cooling the processor with this cooler your cpu without load could be on 22digree celcious and on load it will be on 37 digree celcious and the motherboard is great 8gb ram enough for playing todays games on ultra settings great cpu man