So got a bit of spare cash just laying about, i can't make my mind up what upgrade to my PC to make.........

Currently running:
I7 4790k (oc 4.8)
Maximus Hero mobo
24GB Corsair vengeance RAM
EVGA Nvidia GTX 970 FTW GPU (oc to i can't remember what...)
H100i CPU water cooling
2 x SSD
1 x 1TB hybrid drive
800W gold (something or other) PSU

Do i:

Custom water cool the whole unit (not got a problem with temp, but would make it look sweeeeet)
Get another GTX 970 and SLI the mofo?

Any thoughts/ideas welcome

Many thanks