Help With New System

I was planning on building a new system because of problems with my current computer. This is my first build so I am looking for some help with the parts. I do not want a super computer but I want it to be good for games and school work. Here is what I have chosen. Please give me any recommendations that you have and tell me about anything I am missing. I am planning on using Windows Vista Ultimate.
Case
Power Supply
CPU
Motherboard Is there any advantage for me to get this instead?
Graphics Card
Memory???Any suggestions
Hard Drive
CD Drive
Case
Power Supply
CPU
Motherboard Is there any advantage for me to get this instead?
Graphics Card
Memory???Any suggestions
Hard Drive
CD Drive