Here is my proposed budget build. OS will be LINUX, most likely KUBUNTU 14.04 for now. OS & Application SW on SSD, bulk storage on networked HD.
Used for CAD, embedded controller SW development and eventually freeCAD & Blender 3D printing projects.
Tech Report budget box with a couple substitutions. Would consider Micr0-ATX alternatives.
CPU Core I3-6100
MOBO Gigabyte G1 Gaming GA-H170 Gaming 3
MEM G.SKILL Ripjaws V Series 16GB (2 x 8GB) 288-Pin DDR4 SDRAM DDR4 2400
SSD Crucial MX300 M.2 2280 275GB SATA III TLC
GRAPHICS Gigabyte Radeon RX 460 Windforce OC 4GB
Case Corsair Carbide Series 200R Black Steel
PSU CORSAIR CX-M series CX450 450W 80