Generally I think you should get for a hosting account with a separate domain for your blog. On the other hand a free blog would be fine too if yours would be a personal blog. Depends on your choice.
It totally depends upon for what purpose you want to start the blog. IMO bloggers and wordpress are good options. They provide the user the ability to get a personal blog up and running real fast.
There is only one drawback of using these services is that you are limited to using their standard features and that you are going to end up with a domain name like yoursite.blogger.com
On the other hand if you want get a hosting account with your own domain name. This will allow you to customize the blog with all the plug-ins which are much better than the free services. You will be able to modify or make changes according to the requirements of the blog.