Through the use of custom web design options such as color, logo and customized web applications, you set the brand image in the mind of the client. In today's business world, you cannot afford not to reinforce your brand.
Custom web design is also an important tool in search engine optimization. Although sites cannot be optimized, it is important to personalize your site area to achieve a better page rank. For example, you could have a "Contact Us" page or you can personalize it to read, "Contact ABC Company" for a better effect. Your designer will be able to help you with this. If you are looking for web design services then you can click over here.
It is also important that the logo and corporate colors are optimized for the web. A logo company look great on the letterhead, may not translate well into a web page and you'll need custom web design to address this problem.
In all, whether or not you go with a generic web design is really depends on what you want from your website. If you are really serious about marketing your business and brand, you can not take a "one size fits all" web solution. You can check various online resources to get more info about it.