More information on that below. Each search engine uses its own criteria to rank sites. What works well on one engine will fail miserably on another. Most of them weight the title heavily, then the META tags , then the visible text on the page, sometimes giving more weight to the first few words. With that in mind be sure to put primary key words in the title and use a good META tag.
Titles are extremely important for success with most search engines.
It also helps people figure out where they are on your site. A well designed title has relevant keywords but is also a navigation aid. There are many meta tags, but most of them are useless. For an example of meta tag usage, view the source of this web page to see how I have used them. The meta description tag allows you to control how a search engine displays your listing.