Before you order your business cards, before you design your stationery and envelopes, before you order your signage or contact a webmaster or hosting company, you must come up with a logo for your business. It is square one of your identity. It makes no sense to generate marketing materials that do not contain what is to be your primary identity (your logo). Here is a great article written by Peter Shadbolt on bbc.com. I was shocked to learn what some companies spend on their logo design. It is also worthy of note that your logo may be a moving target, that it will likely undergo changes as the business (or climate) changes.
