To validate or not to validate; that is the question. A List Apart’s own Ethan Marcotte helps us to re-examine our approach to standards advocacy and how we can better educate our clients on the benefits of web standards.
I still prefer that my sites validate but I do allow warnings and occasionally minor errors to get through. It is a tradeoff. I want the sites to validate but I need to limit the amount of time I spend debugging validation problems since I am the only person who cares that the problems get fixed. The biggest advantage to having a site that validates is to minimize the maintenance headaches supporting multiple browsers.