Not a bad setup but I think I would tweak it a little.
I would definitely change the case to something different perhaps the Corsair Carbide 300R Midi Tower Case which has better cooling.
Overclocking might shorten the lifespan of a CPU but as most of us change our PC's after 3-5 years we are never going to have a problem. As to whether overclocking benefits gaming that depends entirely on the game. I would just leave the CPU as it is but perhaps change the cooler to the Corsair Hydro Series H55 Liquid Cooler which in my opinion is the better cooler.
I see this PC comes with 16GB or RAM which is twice what you will ever need but as there is no way to reduce it to 8GB you are stuck with it. Will not do any harm just a waste of money.
I see that this PC comes with a small SSD (128GB0 which is ideal for your operating system and programs but it also comes with a 2TB harddrive as a secondary. I would prefer to see 2 x 1TB harddrives one for your documents, music, videos, ETC and the other for your games. If like me you have a lot of games on Steam then this is going to take a chunk of space.In my case 465GB which is a lot of used space.
I possibly would change the operating system to Windows 7 64BIt as Windows 8 still has it's problems.
As for the monitor I would definitely spend the extra on the Dell UltraSharp U2412M as they are incredible monitors. I have one and a 27 inch and they are the best monitors I have ever had.
Definitely swap the cordless keyboard and mouse to a wired version, gaming and wireless do not work well together.
I think that's about it.