I would suggest something like this for the regular PC's. This will probably run everything maxed out (correct me if I'm wrong). Also I would suggest you to dedicate a double of PCs to streaming (call them streaming booths), make it a bit isolated. For the streaming PCs you should use i7 4790k's or Xeon 1231's. Good luck!
PCPartPicker part list / Price breakdown by merchant
| Type | Item | Price |
|---|---|---|
| CPU | Intel Core i5-4460 3.2GHz Quad-Core Processor | $178.99 @ SuperBiiz |
| Motherboard | ASRock H97 Anniversary ATX LGA1150 Motherboard | $71.99 @ SuperBiiz |
| Memory | G.Skill Ripjaws Series 8GB (2 x 4GB) DDR3-1600 Memory | $54.99 @ Newegg |
| Storage | Western Digital Caviar Blue 500GB 3.5" 7200RPM Internal Hard Drive | $48.98 @ Directron |
| Video Card | Asus GeForce GTX 980 4GB STRIX Video Card | $549.99 @ SuperBiiz |
| Case | Corsair 200R ATX Mid Tower Case | $54.99 @ Micro Center |
| Power Supply | Corsair CX 500W 80+ Bronze Certified Semi-Modular ATX Power Supply | $44.09 @ Newegg |
| Monitor | BenQ GW2765HT 60Hz 27.0" Monitor | $388.99 @ B&H |
| Prices include shipping, taxes, rebates, and discounts | ||
| Total (before mail-in rebates) | $1423.01 | |
| Mail-in rebates | -$30.00 | |
| Total | $1393.01 | |
| Generated by PCPartPicker 2015-03-23 21:22 EDT-0400 |