Just throwing in a recommendation for bang-for-the-buck. I built this system nearly a year ago and it's still relevant right now, especially for gaming.
I came from an overclocked 2500k (at 4.4GHz) and the performance increases were noticeable. The CPU became my bottleneck after I bought a GTX 970.
- CPU: Intel i7 4790k -- I'd still probably get this today. It's better in gaming benchmarks than the last two Intel releases pretty frequently.
- Motherboard: Asus Maximus VII Hero - I'd still get this today, or I'd get an even better Asus. MAYBE the Gigabyte that has the fancy USB that is meant for DACs (but the Asus has them too and it's BS).
- RAM: G.Skill TridentX DDR3 2400 -- This ram rules. The only way I'd get something else is if I got a processor that required DDR4.
- Video Card: Galax GTX 970 HOF -- Overkill. If I did it again, I'd get an EVGA GTX 970 FTW+ (wasn't out yet)
- SSD: Samsung 840 Pro 256GB (would prefer 512 or 1TB, to be honest) -- If I were to build today, I'd get an M.2 if I could afford it, or an 850 Pro if not.
- HD: HGST Deskstar NAS 7200RPM 4TB -- Great for always-on storage and streaming files reliably
- PSU: Corsair HX850 -- Built today I'd get their best 850 or 1000w power supply
- Case: Corsair Carbide 400R or whatever floats your boat -- they make excellent cases
- CPU Cooler: Corsair Hydro H60 or better. -- If you want to OC hard, get one with the full radiator (two fans) and "i" series if you get that PSU. I have the Enermeax Liqtech 240 and it's great but harder to install than Corsair.
- Keyboard: Love the Cooler Master QuickFire Rapid/XT keyboards with Cherry MX Brown. I have the tenkeyless at home and full-size at work.
- Sound Card: Sound Blaster ZxR for gaming.
Did I miss anything?