Could use some advice.... first time builder

For years I kept telling myself that I would just build my own pc and finally decided to do so. Unfortunately after reading many articles and doing what research I could I realized that I am out of my area of expertise when it comes to picking parts, ensuring there are no compatibility issues and just how much I need to spend.

I want to keep the cost down as much as possible while still leaving room for future upgrades. (I'm a poor college student so I need some bang for my buck  ) I intend to use the computer for music, video, school, and the occasional game (mostly WoW).

The only real preference I have is that I do not want to go below my current processor, everything else wide open to suggestions and comments.

Here is what I have so far:
CPU - AMD Phenom II x4 955
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Motherboard - GIGABYTE GA-880GA-UD3H AM3 AMD 880G HDMI SATA 6Gb/s USB 3.0 ATX
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Power supply - CORSAIR CMPSU-650TX 650W ATX12V
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Memory - G.SKILL Ripjaws Series 4GB 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10666) Desktop Memory Model F3-10666CL9S-4GBRL
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

DVD rw -
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

HDD - Western Digital 1.5 TB Caviar Green SATA Intellipower 64 MB Cache Bulk/OEM Desktop Hard Drive WD15EARS
http://www.amazon.com/Western-Digital-Intellipower-Desk...

I still need:
A cheap decent case
A cost effective video card
Probably a cooling system of some kind
Any other input you might have, especially in places where I can save some $$.