Plan to upgrade the MB/CPU/case from a 2500K build. A few parts have been replaced along the way (hard drives, 980 Ti, OS), or are still useful (2x 30" monitors, mouse/keyboard, maybe the Corsair HX850 PSU).
Typically play RPGs (i.e., Fallout 4, The Witcher 3, Wasteland 2) and strategy games...