Canon 300d and 20d are very good at auto WB when color temp is between 4000k and 7000k. The color tone is little bit bias to 'cold'
tone.
Canon 350d is bias to 'warm' tone.
I am not familar with Nikon system. But based on several of friends who use D70, it is bias to 'warm' tone. I am sure whether it is a common issue for D70. 偶尔贴贴 is D70 and D2X user, he knows Nikon better than I do.
If you shoot with RAW file, you don't need to worry about WB. One huge advantage for RAW file is that you can change WB later in Canon's software.
In most time I don't pay much attention to WB. The post processing in PS is easy.
The accurate exposure and shutterspeed is more important in my opinion.
Just my 2 cents. Welcome more comments.