Hi!
well assembled configuration is very helpful for gaming PC however in branded PCs there are such companies like ALIENWARE are helpful to fulfill your requirements in just a glance
All I know from 5 years of experience and now a days of the "technology", here is your answer
your badget is 50000 so I m going with HighENd gaming rig (hey! your budjet is not enough you know!)
*CASE Antec Twelve Hundred
*PSU Tagan BZ Piperock 700w
*CPU Intel Core i7 920 step D0 @ 3.8 Ghz
*CPU COOLER Thermalright IFX-14 + Scythe Ultra Kaze 3000 rpm + C. Master Led
*MOBO Asus P6T X58
*RAM 6 GB G Skill Ripjaws 2000 Mhz @1604 Mhz 7-8-7-24 1T
*VGA Sapphire Ati HD 5870 1 Gb
*HDDs 2x Maxtor DMax22 500 gb 7.200 rpm Raid 0 (update: Intel SSD X25 M 80 gb + Seagate Barracuda 1 Tb)
*BLU RAY REW. LG GGW-H20L
*MULTIMEDIA Antec Veris Elite IR Receiver
*SOUND CARD Creative Sound Blaster X-Fi Titanium
*NEON Revoltec 30cm Blue
*FAN CONTROLLER Scythe Kaze Master
*OS Windows 7 Ultimate 64 bit
*MONITOR Samsung P2470H 24" Full HD 2ms
*AUDIO Creative 5.1 Inspire T6100 (update: Logitech Z-5500)
*HEADSET Creative Fatal1ty Gaming Headset (update)
*KEYBOARD Razer Lycosa Mirror
*MOUSE Microsoft Sidewinder Gaming (update: Razer Imperator 5600 DPI)
*MOUSEPAD Hama Blue Led (update: Razer Sphex)
*PRINTER HP Photosmart C4680 All in One
OK I know it costs but you can reduce accessories and version to reduce price like reduce printer. razer mousepad, reduce i7 to i5, spekers like wise then you can go with your price
and this configuration is for allllll HIGHEND games even your crysis gonna hell OK!