An Open Question to the Community

I have a friend who is involved in starting up a website oriented towards artists and writers. He contacted me to ask what blogs and websites I considered useful and important for writers, probably with a view to posting links.

I gave him a list of some I considered valuable--and, of course, referred him to the esteemed cast of bloggers over on the sidebar of this blog. But I thought I'd throw out the question to all of you folks as well. Are there any writing-related sites you consider especially valuable or prominent?