In general, a very good build. If anything holds it back, it will be the graphics card. You don't state your monitor resolution, which has a bearing, on how well a HD7770 will work. Most games will be playable at 1080p, but high/ultra, in some games will be "a stretch". Obviously, at lower resolutions, it would cope better.
For a gaming build, the video card you chose is weak relative to the CPU you chose. You might not need a stronger card depending on which games you play and on what resolution. It would be nice to have a budget to make other suggestions to you.