I've had both colors in my kitchen, and I'd go with the blue.

Depending on the color of your cabinets, yellow will look really bright in the kitchen. Blonde, white, or any pale colored cabinet will really wash out with yellow, and If your goal is to create a soothing atmosphere, bright yellow will make you feel like you are eating breakfast in a light bulb.

Dull blue can be quite trendy in the kitchen if done the right way. After painting, assess what you have for little extras such as framed photos, artwork, or shelves for knick knacks. Colors that look good with dull blue are black, white, or even brown. Items such as metal signs, wood mount art work with your favorite photos, or wall decals with an inspirational quote look great on kitchen walls.

Add a great rug under your table to really enhance the color of your walls. If you are into traditional decor, you could add a rug like this Pale Blue Oriental Rug. For country decor, a rug such as this Blue Wool Braided Rug would work well. Area rugs really add that extra depth to your decorating.