With your budget, I would buy a Noctua nh-D14 or phanteks assuming you have 160mm height available.
That will really be more than you need, for your oc, but a better cooler can be quieter with slow turning 140mm fans.
I think you may be overkill with that cpu and sli gtx780 on a 1080P monitor.
I might have considered a 30" 2560 x 1600 monitor.
But, since budget does not seem to be an issue, go for it.