Originally Posted by jms698 
White balance is not the issue: I set it to the incandescent preset (auto white balance is hopeless in incandescent light, but spot on in other lighting conditions) and tweaking the color temperature in the RAW file makes reduces the red saturation somewhat, but makes all other colors look wrong.
You don't say what RAW processing program you are using, but WB *is* the issue. If the red channel is clipping, or otherwise dominating the shot, then WB temperature is not set low enough. Apparently the incandescent prese tisn't matching the color of your bulbs well enough. Either customize the wb (using manual wb, or using the in-camera controls to alter the incandescent defaults - at least, I think the K20D supports that), or create a custom wb in your PP program and hit whatever button it takes to apply that present to all your tungset shots (and if takes more than a button press or two to apply a given wb preset to a whole bunch of photos at once, you're using the wrong RAW program).