I made a couple of changes:
PCPartPicker part list / Price breakdown by merchant
| Type | Item | Price |
|---|---|---|
| CPU | Intel Core i5-4460 3.2GHz Quad-Core Processor | $178.49 @ OutletPC |
| Motherboard | MSI Z97S SLI Krait Edition ATX LGA1150 Motherboard | $109.99 @ Amazon |
| Memory | Kingston Fury Series 8GB (2 x 4GB) DDR3-1600 Memory | $62.89 @ SuperBiiz |
| Storage | OCZ ARC 100 120GB 2.5" Solid State Drive | $59.99 @ Amazon |
| Storage | Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive | $44.99 @ Best Buy |
| Video Card | EVGA GeForce GTX 960 2GB SuperSC ACX 2.0+ Video Card | $192.71 @ Amazon |
| Case | Zalman Z11 ATX Mid Tower Case | $74.52 @ Amazon |
| Power Supply | OCZ ModXStream Pro 600W 80+ Certified Semi-Modular ATX Power Supply | $83.99 @ Directron |
| Case Fan | Xigmatek CLF-F1455 60.5 CFM 140mm Fan | $14.43 @ Amazon |
| Case Fan | Xigmatek CLF-F1455 60.5 CFM 140mm Fan | $14.43 @ Amazon |
| Case Fan | Xigmatek CLF-F1455 60.5 CFM 140mm Fan | $14.43 @ Amazon |
| Prices include shipping, taxes, rebates, and discounts | ||
| Total | $850.86 | |
| Generated by PCPartPicker 2015-04-06 02:55 EDT-0400 |
Mainly the motherboard and the SSD, because the motherboard is cheaper and better quality, and the SSD is a far higher quality one than the super old SanDisk without being much more money.
I would also recommend ditching the 960 and going for a second hand 770, as that card will perform a lot better and thus last a bit longer. With the second hand market as it is, you should be able to find one fairly cheap.
If her (and your) budget will stretch to $1000 I'd recommend switching out the non-k series for a K series and fitting a Hyper 212 or AIO, as that should help extend the PC's useful life.