It is always useful to mention what your budget is as it helps if we suggest other components that they are still within budget.
I would add at least a 120GB SSD to your selection as a boot and program drive and also add at least another 500GB Sata harddrive as the single 500GB you have at the moment really is not enough. Just to give you some idea I currently have a crucial M4 128Gb SSD with 77GB free, I also have a 1TB HDD 724GB free and a second 1TB HDD which has nothing but my games including my Steam installation and I only have 477GB free on that one. So that gives you a rough idea how quickly hard-drives fill up.
The rest of your build is fine but I prefer the GTX 670 over the HD 7870 better GPU but more expensive.