That really depends on what you are looking for in a website. Are you looking for instruction? Feedback on your writing? Sources for publication? I have found that one of the best all-around sites is Absolute Write. It is populated with newbies and published writers in every genre. There is information from everything as obscure as what kinds of guns and ammunition did old west gunslingers use(for research in historical writing) to discussions on the legitimacy of publishers and editors when you are ready to submit your work for publication. In fact, Absolute Write is where I found out about Mahalo (Mahalo was advertising for How To writers in the paid for writing gigs forum.

If you are interested in having your peers critique your writing (there is a place for that on Absulute Write) I have used Review Fuse and been pretty happy with it. It is a website where you review other writers and they review you. You can gain alot of insight not only having your work critiqued by your peers, but studying other writer's work as well. I will put a link to Review Fuse in the source section below.

Agent Query and Query tracker are great tools when you begin the query process. They are invaluable in matching you with publishers and agents. Of the two, I like agent query better, as there are so many tools at hand.

If you are looking for markets you might try Duotrope, which is a free writer's resource listing over 2825 current Fiction and Poetry publications.

If you are thinking about ebook publishing, I really like Smashwords. You can upload your work to the website and Smashwords helps market it and makes it available in lots of different electronic formats for a small fee. Over the last six months, Smashwords signed distribution agreements with several of the world's largest ebook retailers, including Barnes & Noble, Sony, Kobo and Amazon. You set the retail price for your work, or if you wish, you can offer your ebook free of charge (in which case Smashwords won't charge you anything to host and distribute your ebook). You can also opt in to a program to distribute your ebook free to American Soldiers serving oversees, which they can download to their kindle. I do that through Smashwords as a way to say thank you to our servicemen and women while they are away from home and family for long stretches of time. Anyway, I digress...

I hope this list has helped you some, but there are lots more I can recommend, if only I knew exactly what you were seeking.

Good luck!