How do i pick which parts i need for a gaming rig ?

2500k is a popular gamers choice because they are good overclockers to get most out of your system.
i can make you a list of compatible parts if you'd like. do you need a monitor too? mouse and keyboard?

Well, there are reviews with benchmarks for the various processors and graphics cards, but that's a bit much to digest if you're starting almost from scratch. Tom's has monthly guides for the best processors and graphics cards for the money:

http://www.tomshardware.com/reviews/gaming-cpu-review-o...

http://www.tomshardware.com/reviews/gaming-graphics-car...

Apart from that, there's always the forum for detailed advice.

A few things to get started on are that for a gaming rig, the overwhelming majority of games are going to be driven by your graphics card performance, with the CPU more of a secondary. A couple of general guidlines would be:

CPU: As stated above, an i5-2500k is a good choice, i-5 3570k is another good choice and is good for overclocking. The i7's would be a waste of money because games really can't take full advantage of them, so it's money better spent on your other pieces.

GPU: Plenty of capable cards out there. This really becomes more of a performance vs. price vs. nVidia/AMD preference. Most people with your budget range tend toward an AMD 7850/7870 or nVidia 600 series.

RAM: Really anything above 8GB combined is unneccessary. Usual recommendation is 2 x 4GB sticks.

Motherboard: Again really personal preference and will depend on what CPU you go with. ATX boards offer more expansion slots for future, but micro ATX offer more affordability.

After market cooler for CPU: This is really only necessary if you are going to overclock your CPU. Usually, the stock CPU cooler is sufficient if just running stock.

Power Supply: Primarily make sure that you get a good brand PSU and that it will cover your requirements, and possibly a little higher than needed for future proofing or if you plan to overclock.

Most peripherals (case, keyboard, mouse, monitor, etc) are going to be more of a personal preference.

A couple of personal suggestions would be to get around a 128GB SSD for your OS and most played games, and then an HDD for other games, media, etc. This will be a HUGE bump in the system startup. I would also recommend using www.pcpartpicker.com to choose your rig. It has the advantages of, if you turn compatability on, only providing you with choices that will work with the parts that you have already chosen, and it will keep track of the power consumption so that you can get a better idea of what size PSU you should need, at least for a stock system.

And as always, any questions about particular brand recommendations on certain parts, or anything else, please let us know! I hope that gives you a good place to start and if anyone sees anything that I missed or that they disagree with, please let me know.

Yeah that would really help, I just need a rig that will last atleast 2 years if possible. In the sense i can play most games without having to worry about framerate issues. In terms of price, the max i am willing to spend is 1500

Here's a build that should do quite well for the next couple of years (or more). No peripherals included though. If you need them too, it's just going to need a few readjustments to fit the budget.

PCPartPicker part list / Price breakdown by merchant / Benchmarks

CPU: Intel Core i5-3570K 3.4GHz Quad-Core Processor ($169.99 @ Microcenter)
CPU Cooler: Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler ($26.55 @ NCIX US)
Motherboard: ASRock Z77 Extreme4 ATX LGA1155 Motherboard ($127.98 @ Newegg)
Memory: Corsair Vengeance 8GB (2 x 4GB) DDR3-1600 Memory ($33.99 @ Amazon)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($49.99 @ Newegg)
Storage: Samsung 830 Series 128GB 2.5" Solid State Disk ($98.49 @ Amazon)
Video Card: PowerColor Radeon HD 7870 2GB Video Card ($219.99 @ Newegg)
Case: Corsair 300R ATX Mid Tower Case ($74.99 @ Newegg)
Power Supply: Antec High Current Gamer 620W 80 PLUS Bronze Certified ATX12V / EPS12V Power Supply ($49.99 @ Newegg)
Optical Drive: Samsung SH-222BB/BEBE DVD/CD Writer ($17.99 @ CompUSA)
Operating System: Microsoft Windows 7 Home Premium SP1 (64-bit) ($99.99 @ Newegg)
Total: $949.94
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2012-11-13 15:03 EST-0500)

OS: Windows 7 Home Premium x64
-MB: Gigabyte GA-MA770T-UD3
-CPU: AMD Phenom II X4 965 3,4GHz
-GPU: Gainward GeForce GTX 570 Phantom
-RAM: G-Skill 4x2GB DDR3 1333MHz

How would you rate that build compared to yours ? and also what settings could i run games such as Battlefield 3 or guild wars 2 ? Also thanks alot for for taking the time to write that.

That build has a much slower CPU, with slower RAM and a slightly slower graphics card. It's also relatively old hardware, so you're missing features like SATA3 and USB3.0.

Your build might just about work for eg. Battlefield 3 at 1080p Ultra (singleplayer). The one I suggested would do it with ease. In MMOs the CPU becomes more important, so Guild Wars 2 or the like might end up chugging a little with your build. And it's hard to fix since dialing down graphics settings mainly eases the workload on the graphics card, not the CPU.