When you search for something in Google, the blue link you see is the title of the page it is listing. For many visitors, that link is a major deciding factor in whether or not they click on the link. Because of that, it is very important to put a good unique title on each page of your site.
Because of the importance of the page title in Google, you should take some time to make sure it is right. Consider the keywords of the site, and more importantly the keywords of that page, and see how you can add some of those keywords into the title. Many experts recommend keeping your character count for the title under 75 characters and that includes letters, spaces, numbers, and special characters (quotation, exclamation, question marks, etc.). You can go over that number, but many leading search engines cut off the title at around 75 characters so be sure to get the keywords in before the 76th character.
The title needs to change from page to page. For many visitors, their first page they get to is the home page, but most every page of your site is indexed by Google (and all search engines) and therefore need to have a good title to help encourage visitors to click on the link