Tom's Hardware did a article on Athlon64 chipsets,
http://www.tomshardware.com/motherbo...105/index.html
Just incase you wanted more info on chipsets supporting the Athlon64.
I am not sure about that video card you have selected. From what others have said, SE versions of video cards are good to stear clear from. If you want to keep your price for a video card under $200, then i would suggest an ATI 9600XT, but i am not sure if the drivers off of ATI's website will work in a 64bit environment.
Other than that, looks like you will be having some fun. Have you thought of which distro of Linux you are going to use?