I recently heard someone say, "do you really need a website? I mean isn't that what facebook is for?". While social media does help create a presence for many businesses, it's not a website and shouldn't be used as such. Social media should be part of your overall web presence, but not your customer's only source for finding out about who you are and what you do.
What does this look like? A website makes your company visible to the general public 24 hours a day 7 days aweek and because of that it should represent you well. When you've called it a day and no longer have the energy to keep going, your website is still hard at work, unphased by the days activities. With that in mind, your site should have images that convey who your company is and how you operate. It should also have content that "sounds" like you. We all have a voice that comes out in our writing. Customers know when it's not you and they know when the writing sounds generic. Be yourself.
There's also the customer perspective, when I've found a new company, I always google them, check the website, maybe see what they're doing on social media, but regardless I always search for their site. This is how I find out about the company, find where they're going to be, or where their business is located (those last two can be very different). Regardless of whether I want to read up on a product or just check the hours of operation, making this information available and easy to find is critical. Your site and how well it functions could either remove or put up a barrier for the customer.
What to Remember: a good website is different from that thing you call a website that hasn't been touched in years...