Intel Core i7-4770 Haswell 3.4GHz LGA 1150 - $299.99
ASUS MAXIMUS VII HERO LGA 1150 Motherboard - $219.99
G.SKILL Ripjaws Series 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 - $79.99
SAMSUNG 840 Pro Series MZ-7PD256BW 2.5" 256GB SATA III SSD - $199.99
EVGA SuperClocked 02G-P4-2662-KR GeForce GTX 660 2GB - $219.99
Corsair Carbide Series 200R ATX Mid Tower Case - $59.99
Thermaltake ToughPower Grand TPG-0650M - PSU - $109.99
LG Black Blu-ray Burner SATA WH16NS40 - OEM - $64.99
Dell U3014 Black 30" LED Backlight LED Monitor (2560 x 1600),IPS panel - $1199.88
Microsoft Windows 8 Professional 64-bit (Full Version) - OEM - $139.99
Price: $2594.79
Keep in mind that you'd still need a mouse, keyboard, and at least 1-2 additional fans inside the case for cooling, plus any other items you might want in the machine. While you could go with a cheaper monitor, you would sacrifice either screen size, resolution, or brand reliability in the process. I included the Blu-Ray burner because you pretty much have to have an optical drive to do anything in Windows, since most Windows software still comes on discs unless you use services like Battle.net, Steam, or Origin for games. There is no true equivalent on the processor side, as the mobile parts have different clock rates, TDPs and even form factors from their desktop counterparts.
Why would you use newegg when you have pcpart picker?
http://pcpartpicker.com/p/QpZtQ7
PCPartPicker part list:
http://pcpartpicker.com/p/QpZtQ7
Price breakdown by merchant:
http://pcpartpicker.com/p/QpZtQ7/by_merchant/
Benchmarks:
http://pcpartpicker.com/p/QpZtQ7/benchmarks/
CPU: Intel Core i7-4770 3.4GHz Quad-Core Processor ($299.98 @ OutletPC)
Motherboard: ASRock H87 Performance ATX LGA1150 Motherboard ($119.99 @ SuperBiiz)
Memory: G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-1600 Memory ($72.00 @ Newegg)
Storage: Samsung 840 EVO 250GB 2.5" Solid State Drive ($139.00 @ Amazon)
Storage: Western Digital Caviar Black 1TB 3.5" 7200RPM Internal Hard Drive ($88.97 @ OutletPC)
Video Card: EVGA GeForce GTX 760 2GB Video Card ($239.99 @ NCIX US)
Case: Corsair Carbide Series 300R Windowed ATX Mid Tower Case ($79.99 @ Amazon)
Power Supply: Corsair CSM 450W 80+ Gold Certified Semi-Modular ATX Power Supply ($59.99 @ Amazon)
Optical Drive: LG GH24NSB0 DVD/CD Writer ($14.99 @ Newegg)
Operating System: Microsoft Windows 8.1 (OEM) (64-bit) ($89.98 @ OutletPC)
Monitor: Asus PB278Q 27.0" Monitor ($466.60 @ Amazon)
Total: $1671.48
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2014-06-01 13:11 EDT-0400)
Macs are nice but please don't try to spin this into something else.
(Yes my selections may not be the best but they give a pretty good idea).
You are getting significantly more CPU power (full turbo), much more GPU power, more storage, and a nice large usable monitor (a 27" 1440p is just as useful if not more as 15.4" 1880p due to the much larger amount of real estate). I've shaved over $900 off the previous build.
You would need a mouse and keyboard/speakers but those can be used for multiple builds and if you had a previous desktop you could use those (alternatively the monitor, case, ODD, HDD and SSD can be resused making subsequent builds even cheaper).
Apple provides nice computers and has OSX but from a pure value perspective rmbp can't compare.