I have worked on a number of rebranding projects for large companies, and can tell you color is very important.
Color gives the subconscious context to what your brand is about. For instance, most Eco brands tend to use Green as a base. This is also why McDonald's spent millions recently in changing all the designs of the Mcdonald's in store and branding from red to green. Blue typically denotes many business to business companies. Look at IBM, AT&T as examples. Depending on what your business is, will also determine how much the color scheme will define who you are to the market.
The relative importance of color will vary within sectors and product categories but color (or even its relative absence) is usually a key and multi-faceted signifier among the elements that combine to build core a brand identity—as well as in your supporting marketing materials, sales tools, and certainly in products themselves.
Not giving it due consideration before deploying a major campaign will definitely not help you differentiate yourself visually and may affect both brand perception and resulting sales.
And, it can be counterintuitive: color in fashion, especially at the high-end, is often less important in core branding elements (logos, for example tend to be monochromatic, classic marks) but is vital in seasonally differentiating products such as a clothing collection and or accessory line which is also reflected in ad campaigns. But there are always exceptions: http://us.christianlouboutin.com/ is known as much for the red sole as for the ever changing shoes they are attached to. The red of the sole is visible from a much longer distance, and multiple angles. than the logo, itself.
If I say John Deere, you will think of a color; if I say Caterpillar you will think of another. Companies will fight tooth and nail to embed specific color triggers into our connection to them and protect such color as part of their intellectual property. Evidently, they think color deserves much consideration.
It depends on your business. Were it a food retail or gross sale color scheme would be fundamental, but without being trivial everything involving esthetics as an important feature to buy for, should have a professional analysis of color palettes and schemes: it is the most important rule in marketing and in designing.
Said that any other consideration is useless if you don't get to the point of what your business is.
You likely won't get it right the first time around. Though it will make a difference. There was an interesting study about how waitresses who wear red lipstick receive 30% higher tips. When asked why they tipped more, they had no idea. Not every decision is conscious.