LiveJournal.com is a free service for all your journaling and blogging needs, offering privacy controls, photo storage, publishing tools, style templates, and online communities for just about every interest imaginable.
LiveJournal actually seems to have more individual options than a lot of other blogs, suitable for teens to seniors. Not only can you make your own posts private or public, you can easily search for communities of interest and join those communities. (Examples range from anime to pets to single parents to daily cat pictures, and plenty more.) I have had an account with LJ (free) for many years and have developed some great freindships through the communities in LJ. If you are tired of the immaturity of MySpace and the awkwardness of Twitter and the extreme limitations of many other blogsites, I would strongly suggest giving LJ a try!