White or black background is a old diatribe, specially when you are talking with a die hard Cad monkey.
I used to say it was a matter of taste, until I read some scientific papers proving that black background (blackground?) is bad for your productivity.
Try to get your hand on this reference study:
Effect of Image Polarity on VDT Task Performance
Harry L. Snyder / Jennie J. Decker / Charles J. C. Lloyd / Craig Dye
http://oldwww.acm.org/perlman/hfeshci/Abstracts/90:1447-1451.html
It states clearly:
"Three experiments were conducted in which positive and negative contrast on visual display terminals were directly compared. Operator tasks included visual search and reading, with accuracy and timeliness of response measured. In all cases where significant differences exist, better performance was obtained with negative contrast (dark characters or symbols on a lighter background). The increases in performance range from a low of 2.0 percent to a high of 31.6 percent."
Increased performance as much as 31.6%!
Forget 64 bits, quadcore, 30" displays. Change your background to white, and you will be 30% more productive. Without spending a dime.