I haven't noticed this bias in myself. In fact, one of the comics I read daily -- GPF -- went to color and I didn't even notice. (Happened sometime in 2002 or 2003, I guess). Out of the 21 strips I regularly follow, nine are in color. But most of those were in b&w when I started reading them, so color didn't have an impact on my decision.
Perhaps more interestingly: I only read a handful of strips where I know the creator's sole income is from the strip. Those would be: Megatokyo, PVP, Sluggy Freelance, and User Friendly. None of those run daily color strips (though the last three do Sunday color).
But this has been on my mind, so I thought I'd do a little poll on it and a couple of questions. For variety, I'll fill out my own poll this time. :)
Do you think you're more likely to read a color strip than one in black and white, or greyscale?
About how many webcomics do you follow?
About what portion of the comics you read are in color? (Please count strips that are usually in b&w, but have color on Sundays or other rare occassions, as "not in color")
Is art or writing more important in a comic strip?
How frequently does a webcomic have to update to get you to follow it?
What annoys you most in a web comic?
What do you most want to see in a web comic?