Hi there,
I can give you a solution that I feel will satisfy anyone who wants to know what kind of specs to look for to play Battlefield 4 comfortably, without having to really break the bank.
Motherboard: ASRock Z77 Extreme4 Motherboard -
Outstanding value for features, as well as overclocking capability on the Z77 Chipset.
Has SLi Compatibility as well, for the sake of upgrading later down the track if you choose.
CPU: Intel Core i5-3570K -
The main difference with this and i7-3770K is the hyperthreading feature, as well as an extra $100 on the price tag. Hyperthreading is not really being taken advantage of by developers, so this is a great processor at the end of the day, for a great price. NB: You can expect the cost of Z77 and Ivy Bridge processors to go down with the release of Haswell processors coming up.
CPU Cooler: Corsair H100i Liquid Cooling unit -
This is a great solution for overclocking the i5-3570K from 3.2 to 4.5GHz. This cooler has a great reputation in Gaming PC builds, and also is very easy to install. The H100i gives the solution of liquid cooling, without the fuss of a custom loop with tubing, compression fittings, blah blah... All in all, you can't go wrong with this cooler.
RAM: Corsair Vengeance 8GB (4x2G) CL9 @ 1600MHz -
This is a very trusted brand and reliable model of RAM used for gaming, but also very common so you shouldn't have any issues finding these. You should never need to go for anything more than 8GB of RAM, so at it's price, the value to performance has a great reputation.
Graphics Card: Nvidia GTX 660Ti 2GB or AMD Radeon HD 7950 3GB -
660Ti is great in games, capable of running Battlefield 3 at 47fps (ULTRA SETTINGS) at an average (Playable would be about 30fps) so this is very comfortable to play on. The 660Ti has CUDA core technology, which will definitely speed up any type of development or rendering programs you may use - Photoshop, Black Magic, etc.
The 7950 on the other hand, performs slightly less within Battlefield 3, at an average fps of 42 AT ULTRA (keep in mind, the 7950 is CHEAPER). Where it lacks in FPS, it makes up in it's memory bandwith of 3GB, compared to the 2GB 660Ti. This means that the 7950 will be more capable of handling very GPU intensive games, that require a lot of resources to run. This also takes stress off the CPU, reducing the chance of bottlenecking the performance of your PC.
For sheer performance - 660Ti
For price to performance - 7950
With this build, i'd say you'd easily be able to play BF4 at 40-50 FPS on High Settings.
NB: This is only a prediction since the system reqs aren't released yet.
If you have any questions, i'll be happy to help.
-Ozaki141