/sinister laugh hehehehe
Okay
Depending on how you use your other UBS'd hardware - you could move your USB extension bracket to the lower (or top) most PCI bracket - give you more of a tight/snug fit with the cables and see if you can tuck them between the mobo+tray or route the cables under and between the GPU and the slots.
The 24pin mobo connector looks a lil too slack - get it tightened and it'll look sharp along with the 2x PCI-E cables that need to come from above the GPU instead of the side. From the angle at which you've taken the pic - you could manage to hide some of that USB 3.0 cable with the PCI-E cables coming out of the port the 24pin pops out of and swooping it over the card.
The FP (I/O) cable can come out of the port near the PSU to look like they ran parallel to the vertical edge of the mobo.
Move HDD to lower most bay.
The only additional hardware you'll need to liven the rig up would be some ziptie mounts, a bag of zipties - 3~4"+7" and a ram kit in blue or black - i know i know, you go the G.skills as a promotional offer
😛 but the red dimms have offset your blue, black and white theme.
Seriously though, with the hardware you have and the way you've worked on it - I have nothing bad to say about it [:lutfij:3]
Some examples made with my rig
^ they're stealthy but are obvious once you pay attention to the cables directions.