Colour matters always. I know that the function of an item is not hindered by the colour, but how I feel about the item is based upon the colour. If I want this dildo that comes in Colours A and B and I don't like A, but that's all that's in stock... I'll wait for Colour B to come back.
Honestly, color does influence my decision in everything! Can't help it. Especially if it's clothing of any sort -- lingerie, daily clothing, etc. I always go for bold, bright colors and even with toys. Neon green, Pink, purple, lovely blues always appeal more to me.
If I can get it in pink and black it usually becomes mine. I am trying to branch out in the colors of lingerie I own. Color really doesn't influence whether I get it or not if its cute and in my size usually I will get it.