Well don't drive yourself crazy trying different foods. You will end up making the pickiness worse. Here is a good site to help you evaluate different dog foods:
Dog Food Analysis - Reviews of kibble
My two eat Natural Balance, the Limited Ingredient Formulas, there are several flavors in canned and kibbles. They get a little canned for breakfast, free fed kibble, and a little canned for dinner.
A lot of people swear by feeding the raw foods, there are different brands that come either frozen or freeze-dried (and you soak in water to reconstitute). I haven't given mine that yet, but have thought about it. From what everyone says, their dogs love it and gobble it right up.
Good luck in finding a food for your picky little one. It seems to be a breed trait
