I have found side intake fans to perform the best, providing outside air to the HSF on the cpu. I use two 120 mm fans (larger fans are quieter than smaller fans pushing the same amount of air) mounted on the left side panel. One cools the video card, the other the cpu and northbridge area.
I found no significant aid in a front fan, as most cases do not have room for a large fan.
I have a 120mm side intake in my old donor case and never had any problems with temps...
I'm currently running my new case with the sides off while I'm testing and fitting new components, but I'm planning a window or custom cut that includes a similar 120mm side intake
I got a combination of retail and DIY rounded cables to help with the airflow, and also rerouting or zip tied the rest of the cables to make a much clearer case...
It looks better, and the temps are slightly better