New system
CPU: i7 5960x Extreme 8 core/16 thread processor
Mobo: Asus Sabertooth X99
Memory: 32GB DDR4 Quad Channel
Graphics: Asus Strix Nvidia GTX 970
Storage: 240GB SSD system drive, 3TB secondary drive, 2x2TB Raid 0 scratch disk, 240GB SSD cache dedicated, 4TB backup storage
CPU Cooling: Noctua D15 air cooler (sucker is HUGE!)
Power: Seasonic 1050W
Case: Coolermaster Cosmos II Ultra Tower
If I overclock the CPU (why wouldn't you with an Extreme edition chip and that big ass cooler?), I will at least get it to the same level as my previous system to at least 4Ghz. For me, first and foremost, stability is far more important than trying to benchmark performance. There's nothing more frustrating than putting together a new system and then trying to use it only to have it crash repeatedly while doing important work.
This is replacing my old rig which I still plan to keep and use as backup, renderfarm, and in case I need to access any old legacy stuff.
Old system
CPU: i7 990x Extreme 6 core/12 thread processor
Mobo: Asus Sabertooth X58
Memory: 24GB DDR3 Triple Channel
Graphics: Nvidia GTX 570
Storage: 256GB SSD system drive, 3TB secondary drive, 2x1TB Raid 0 scratch disk, 240GB SSD cache dedicated, 3TB backup storage
Power: Seasonic 1050W
Case: moving into Coolermaster HAF-922 mid tower
spares
CPU: i7 4770s, i5-4360T, i5-2500K
If I end up building another rig with the spare parts I have, I may just end up ponying up the money for the newly released GTX 980Ti and just move the GTX 970 into the HTPC rig (well if it fits) rather than go with something smaller.