Absolutely! SEO is for opportunists, but the web is about people! Optimize for people and long term you can't go wrong.
~Five years from now search engines won't be nearly as important — blogs, tagging, social networks, digg-like services and more that I don't yet know about will make give users new ways to deal with information beyond the search enginees. URLs help people connect to content, and good URLs help people who do the connecting.
Web publishers choosing to optimize their URLs for people is one of the smartest things theyh can do today, and especially for the future.