Smashing Magazine has put up a list of different things that you can do to extend your WordPress blog, and how it functions through custom fields. I’ve heard that this is going to get easier to use in future versions of WordPress, but for now, this should inspire some great additions to your blog.
In this article, we’ve compiled a list of 10 useful things that you can do with custom fields in WordPress. Among them are setting expiration time for posts, defining how blog posts are displayed on the front page, displaying your mood or music, embedding custom CSS styles, disabling search engine indexing for individual posts, inserting a “Digg this” button only when you need it and, of course, displaying thumbnails next to your posts
I can’t really think of anything that’d require expiring blog posts, but the others are very helpful. Check out the whole article on Smashing Magazine, and let me know what you think was most helpful.