1st off if you did a little wire clearing it would help out tons in your cases airflow. if you have a spot on the side panel for a couple fans that should help out alot and make sure to dustout those cards...
There should be plenty of room behind the motherboard for all the cables. I see that its a modular PSU. Are you using every cord from it? Are there some that you can double up on? (ie, SATA used on the hard drives and CD drives instead of two different cables.)