CPU+ Mobo: ASROCK H81M-HDS + i3 4160 (238)
RAM: CRUCIAL PC 12800/1600MHZ DDR3 CL11 VALUE RAM (8GB) (97)
GPU: POWERCOLOR R7 260X 2GB TURBODUO (179)
SSD: CRUCIAL MX100 256GB (159)
HDD: TOSHIBA 1TB 7200RPM (69)
DVD-RW: LG 24X DVD-RW SATA OEM (25)
PSU: SEASONIC S12G NON-MODULAR 550W (105)
Case: DEEPCOOL TESSERACT (65)
OS: WINDOWS 7 HOME PREM (130)
Networking: INTEL AC 7260 PCI-E (79) (Laser Distributer)
Total cost: $1146
Unless otherwise stated, buy at PC Themes, #04-15, and ask for discounts. DIY yourself. If you can't into DIY, get PC Themes to assemble for you for a fee.
Notes:
1) The R7 260X is more than enough to play DOTA 2 and CS:GO at max settings in 1080p, getting a more powerful GPU is not likely to improve your gameplay experience unless you have got a 120/144Hz monitor.
2) The Intel AC 7260 PCI-E wifi adapter is capable of supporting data transfer rates up to 867Mbps and thus has a reduced chance of bottlenecking your internet connection.