Noob has questions about cooling inside the case

[RisingSun]

I'm making plans to build my own rig using the AMD Athlon X4 with the Gigabyte 880GA mobo. I need to decide what case to use. Will any ATX case for sale at Newegg work?

I currently have a Dell Dimension 5100, and it apparently only has one fan. It sits in front of the CPU heatsink, sucks air in from the front, blows it across the heatsink, and then out the back. I don't find any cases at Newegg that do that. The cases at Newegg seem to be using more than one fan. If there is a fan on the back, and a fan on the side blowing air out, that seems like it would interrupt the flow of air from the front. Do you recommend a fan on the side? These cases are 120 front, 80 side, 80 rear.

 

[Rocko]

Side fans are supposed to pull cool air in, onto the CPU/GPU(s). The front fans are supposed to pull cool air over your hard drives. The rear and top fan(s); if applicable- are meant to be exhaust fans.

Edit: fan placement is not depicted in the picture, only suggest air-flow.

 

[ScottALot]

Get an NZXT Beta EVO .... it's real basic and it'd be a no-brainer for airflow.