I don't think a new PSU is gonna make a huge difference tbf.
It looks like linwelin's extensions idea will be your best bet, hiding any excess cabling behind your mobo, I guess from looking at pictures of the
case it's got reasonable space there, it doesn't matter what that looks like. You should be able to route all the cables behind the mobo/side.
I assume at the moment you are having to use 2 cables for the HDD and CD/DVD drive as 1 isn't long enough. Using this extender should make it long enough to reach both using 1 cable, again hiding any excess cable round the side of the case out of sight. Giving you 1 less cable out of the PSU.
http://www.overclockers.co.uk/showproduct.php?prodid=CB-057-AK
EPS = 8 (4+4) pin, ATX = 4 pin.
The EPS is backwards compatable with ATX you just use half of it, which is what your are doing.
Any extension you get either needs to be an ATX 4 pin or EPS 8 pin that is splitable, I don't think the bitFenix does.
This one does, Akasa 8-Pin 30cm PSU Extension Cable.
http://www.overclockers.co.uk/showproduct.php?prodid=CB-022-AK
NZXT 24-Pin ATX Black Sleeved 25cm Extension Cable
http://www.overclockers.co.uk/showproduct.php?prodid=CA-066-NX
I'd be surprised if your need this, but in case for the graphics card.
NZXT 6 Pin PCI-E Black Sleeved 25cm Extension Cable
http://www.overclockers.co.uk/showproduct.php?prodid=CB-001-NX
Hope that makes some sence.