If you want to spend all of those 2500$ then get the top of the line 5950x, 32-64gb of ddr4 32/3600 and a good x570 mobo (i reccomend asus because they are rock solid), you can go figure out the rest of the parts like ssd or some other things, i also dont reccomend spending over 100$ for a fancy case since thats a waste of money.
If i had that much money i would problably build a 24 core dual e5 2678 v3 for running vms, playing games and other productivity things, an rx 6800 (xt), 256gb ddr3 1600 ecc, a custom waterloop with a few 360mil rads, 2-10tb hdd storage, 64gb intel optane ssd (using primocache as it doesnt support an old system like this), 1 or 2 800-1000w 80+ gold server psus, and if i do have some extra money, fill all the pcie lanes that arent used (including m.2) with tesla k80 gpus for gpu acceleration and problably mining/folding.