If you’re not interested in changing your title tags on a post-to-post basis, then this is a good solution to show relevant titles to the page that the user is on.

<title>
<?php
if (is_home()) {
echo bloginfo('name');
} elseif (is_404()) {
echo '404 Not Found';
} elseif (is_category()) {
echo 'Category:'; wp_title('');
} elseif (is_search()) {
echo 'Search Results';
} elseif ( is_day() || is_month() || is_year() ) {
echo 'Archives:'; wp_title('');
} else {
echo wp_title('');
}
?>
</title>