WordPress.com just recently enabled autosave functionality while writing posts.  This seems like an insignificant addition, but I think it's extremely significant.  Several times in the past, I was writing a post (usually long, in-depth, and unfathomably awesome) and I accidentally clicked a link or pressed a magic button on my keyboard that made me navigate away from the post-writing page or just completely erase everything I had written up to that point.  This is incredibly frustrating and completely impossible to undo.  But with an autosave feature, there's no reason to worry about it ... except for the fact that regular WordPress won't have this functionality until the next major version.  Enter the Twilight Universe Autosave plugin.  This plugin automagically (finally, I used that stupid word) saves the post content so that if you accidentally navigate away from the post-writing page or close the window, you can go back to the post-writing page and get the contents of the post.  It doesn't store the post's title or category, but that's not a big deal.  It's also a little buggy, but for the purpose it serves, it's worth it.  So until WordPress comes prepackaged with autosave, I'm using this plugin.