What could I upgrade?

I am planning on building an ITX gaming pretty soon. I have about $95 left in my budget and was wondering what i could possibly upgrade. This is the system right now:

i5 3570K

16GB DDR3 1600 (8GBx2)

Gigabyte GA-Z77N-WIFI

Corsair H80i

Bitfenix Prodigy

Silverstone 600W 80 PLUS Gold PSU

EVGA GTX 670 2GB

I am using my existing ODD and 320GB 7200rpm HDD.

What could I spend more money on to improve performance? Any suggestions would be appreciated.

Thanks!