Here is a simple, reliable, and very FAST regular desktop.
PCPartPicker part list:
http://pcpartpicker.com/p/GJnzFT
Price breakdown by merchant: http://pcpartpicker.com/p/GJnzFT/by_merchant/
CPU: Intel Core i3-4150 3.5GHz Dual-Core Processor ($118.98 @ SuperBiiz)
Motherboard: ASRock H97M Micro ATX LGA1150 Motherboard ($75.66 @ Newegg)
Memory: G.Skill Ripjaws Series 8GB (2 x 4GB) DDR3-1600 Memory ($73.99 @ Newegg)
Storage: Crucial M500 120GB 2.5" Solid State Drive ($72.00 @ Amazon)
Storage: Seagate Barracuda 2TB 3.5" 7200RPM Internal Hard Drive ($83.97 @ OutletPC)
Case: Cooler Master N200 MicroATX Mid Tower Case ($39.99 @ Newegg)
Power Supply: Antec EarthWatts Green 380W 80+ Bronze Certified ATX Power Supply ($34.99 @ Newegg)
Total: $499.58
Prices include shipping, taxes, and discounts when available
I don't see any reason for you to even get a video card, but if you want one,
PCPartPicker part list:
http://pcpartpicker.com/p/BYdLwP
Price breakdown by merchant: http://pcpartpicker.com/p/BYdLwP/by_merchant/
CPU: Intel Core i3-4150 3.5GHz Dual-Core Processor ($118.98 @ SuperBiiz)
Motherboard: ASRock H97M Micro ATX LGA1150 Motherboard ($75.66 @ Newegg)
Memory: G.Skill Ripjaws Series 8GB (2 x 4GB) DDR3-1600 Memory ($73.99 @ Newegg)
Storage: Crucial M500 120GB 2.5" Solid State Drive ($72.00 @ Amazon)
Storage: Seagate Barracuda 2TB 3.5" 7200RPM Internal Hard Drive ($83.97 @ OutletPC)
Video Card: EVGA GeForce GTX 750 1GB Video Card ($99.99 @ Newegg)
Case: Cooler Master N200 MicroATX Mid Tower Case ($39.99 @ Newegg)
Power Supply: Antec EarthWatts Green 380W 80+ Bronze Certified ATX Power Supply ($34.99 @ Newegg)
Total: $589.57
Prices include shipping, taxes, and discounts when available
You gave such a broad budget (400-1000) so that means just about anything is an option, but I can't imagine spending more than $600 on core parts for your uses. You may spend a couple hundred on peripherals too.