If you have spent more than a few hours on the internet then you've probably noticed a variety of page titles, ranging from bland and non-descriptive all the way to downright misleading. Most cases of poor web page titles are due to a lack of understanding. For example, have you ever seen a web page title that read some thing like:
"Blue Widgets, Blue Widget, The Blue Widget Company, Best Blue Widgets, Cheap Blue Widgets, Wholesale Blue Widgets, Buy Blue Widgets"
That is a case of a website owner using outdated SEO (search engine optimization) techniques in an attempt to improve their ranking. Not only does this not work, it also drives real people (the ones who would otherwise be purchasing these wonderful blue widgets) away.
You have also probably seen websites where every single page has the same title, which is usually the company's name. While this isn't a case of a website owner trying to manipulate their ranking, it also isn't helping them increase conversions.
Both from an SEO perspective and from a overall marketing perspective, the most effective title is one that offers an accurate description of the page, yet short enough to display completely in the search engine results pages. In most cases, 60 characters or less will be adequate to describe a web page and still display completely in most search engines.