what would be the best gaming desktop i could build for 350

Solution
PCPartPicker part list / Price breakdown by merchant

CPU: AMD Athlon X4 760K 3.8GHz Quad-Core Processor ($74.99 @ Amazon)
Motherboard: ASRock FM2A88X Extreme4+ ATX FM2+ Motherboard ($60.99 @ Newegg)
Memory: G.Skill Ares Series 4GB (1 x 4GB) DDR3-1600 Memory ($39.99 @ Newegg)
Video Card: Sapphire Radeon R7 260X 2GB Video Card ($123.98 @ Newegg)
Case: Thermaltake VL80001W2Z ATX Mid Tower Case ($24.99 @ Micro Center)
Power Supply: EVGA 500W 80+ Bronze Certified ATX Power Supply ($32.99 @ NCIX US)
Total: $357.93
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2014-10-24...
Without OS its going to be tough yet achievable , here you go ( slightly over your budget ) : PCPartPicker part list: http://pcpartpicker.com/p/X7PpVn
Price breakdown by merchant: http://pcpartpicker.com/p/X7PpVn/by_merchant/

CPU: Intel Pentium G3258 3.2GHz Dual-Core Processor ($69.98 @ OutletPC)
Motherboard: ASRock H81M-HDS Micro ATX LGA1150 Motherboard ($49.99 @ Micro Center)
Memory: Team Vulcan 8GB (2 x 4GB) DDR3-1600 Memory ($67.99 @ Newegg)
Video Card: EVGA GeForce GTX 750 Ti 2GB FTW ACX Video Card ($129.99 @ Amazon)
Case: Cougar Spike MicroATX Mini Tower Case ($29.99 @ Mwave)
Power Supply: EVGA 430W 80+ Certified ATX Power Supply ($34.99 @ NCIX US)
Total: $382.93
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2014-10-23 20:25 EDT-0400

 
PCPartPicker part list / Price breakdown by merchant

CPU: AMD FX-4300 3.8GHz Quad-Core Processor ($88.75 @ Amazon)
Motherboard: MSI 760GMA-P34(FX) Micro ATX AM3+ Motherboard ($46.99 @ Amazon)
Memory: G.Skill Ares Series 4GB (1 x 4GB) DDR3-1600 Memory ($39.99 @ Newegg)
Video Card: Sapphire Radeon R7 260X 2GB Video Card ($123.98 @ Newegg)
Case: Thermaltake VL80001W2Z ATX Mid Tower Case ($24.99 @ Micro Center)
Power Supply: Corsair Builder 430W 80+ Bronze Certified ATX Power Supply ($29.99 @ Micro Center)
Total: $354.69
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2014-10-23 21:19 EDT-0400
 
PCPartPicker part list / Price breakdown by merchant

CPU: AMD Athlon X4 760K 3.8GHz Quad-Core Processor ($74.99 @ Amazon)
Motherboard: ASRock FM2A88X Extreme4+ ATX FM2+ Motherboard ($60.99 @ Newegg)
Memory: G.Skill Ares Series 4GB (1 x 4GB) DDR3-1600 Memory ($39.99 @ Newegg)
Video Card: Sapphire Radeon R7 260X 2GB Video Card ($123.98 @ Newegg)
Case: Thermaltake VL80001W2Z ATX Mid Tower Case ($24.99 @ Micro Center)
Power Supply: EVGA 500W 80+ Bronze Certified ATX Power Supply ($32.99 @ NCIX US)
Total: $357.93
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2014-10-24 14:53 EDT-0400
 
Solution