WordPress is likely to be the best option for a blog. There are cases where it won't be, but more often that not it is. It's great because it's easy to setup and get going very quickly. However, you still have the option to customize as much as you want, when you want. It can also grow as your needs change - you won't be stuck with "just a blog" if you need the site to do more later on. It's great from an SEO perspective, and there are a vast number of plugins available, many of them excellent quality.
