It seems nobody here understands the major differences between the 4820 and the 4770, so I'll explain:
First, the similarities:
1. they're both about the same default speed (the 4770 is a bit lower in clock rate but more efficient)
2. they're both quad core
Differences:
1. 4820k has no integrated GPU, so no QuickSync
2. 4820k has quad channel memory and double the capacity. if you need >32GB of memory, or want to use 4 older stick, the 4820 is more useful
3. 4820k has 40 PCIe lanes while the 4770k has only 16. If you want to use multiple large lane PCIe devices, triple or quad SLI, dual SLi with a raid controller or 10Gbe, etc, the 4820 is better
4. The 4820k had VT-d where the 4770k does not. If you want to run a VM host, the 4820 is far better, but this doesn't work very well with gaming since installing Hyper-V in Windows 8 locks the clock speed at the chip's default, non-turbo mode.
5. the 4770k is lower power and more efficient at the same clock rate. If you want to save power or overclock, the 4770 will do better. The 4820 is still quite capable, though. At idle, the 4820 and motherboard uses only about 20W more power.
As for my opinion, I would go with the 4820, but I'm using dual SLi with an enterprise level raid controller. So, I need the more PCIe lanes. In the end, to each their own.
So, stop badmouting the 4820k as being overkill for gaming. There are good reasons for using it in a gaming machine.