Cookies are associated with tracking user behavior for advertising purposes. So if you really don't need them don't use them. If your web site requires the use of cookies explain why they are needed. For example to support sessions or to remember settings (for example for posting comments on a blog).
Some browsers let the user decide if a cookie is accepted or not make sure that your site still can be used, or give a clear explanation if (parts) of your site don't function with cookies disabled. Don't rely too much on cookies.