Funny, I'm the opposite - I'd LOVE a solid black or bi-color! Of course it has to be a longcoat.
Now that we have Halo, I wouldn't mind another sable, which was probably my least favorite color/pattern prior to that.
Color should not be the only criteria or even the most important criteria, but I agree with Jane. If you have a breeder you're considering, (or a few breeders) that are producing dogs with the kind of temperament that you're looking for I see nothing wrong with preferring a particular color, and hoping that there are pups in the litter that will meet your requirements as well as being the color you want.