Having a blog only means that you're committed to continually providing new content on a regular basis. If you're not committed, visitors may be put off by outdated articles when visiting your website.
A full website, on the otherhand requires static product and service pages. How many really depends on whether you're an e-commerce site and how many products you're offering online.
Both require time for management. Again, each needs a level of committment to truly be successful online.