I personally think that cohesiveness is more important than anything, but that may just be because I refuse to do the white background thing ;) I love what you have now, it's very clean and doesn't distract from the jewelry. I think that as long as your background choices enhance your work and are in line with the overall look and feel of your shop that you can't go wrong. Also, I've seen plenty of shops on here with all white backgrounds and really...ahem...'questionable' picture quality, and it does nothing for their items. I say keep up the great work! I especially love the bark background you use, the contrast between the rough natural material and your bright & modern jewelry is fantastic.