Let's take each in turn. Firstly Title. How important is it…? Well, the title meta tag is what is displayed in your browser window's title bar. For example, the title tag "Buy a Car Today" would mean that the browser title bar would display that text, exactly as it appears in the meta tag. The title meta tag should also contain your business and/or your domain name. It will also be the name under which that page is saved in favourites unless the user chooses to change it.
Most search engines give more weight to words found in the Title, especially if those words are also found in the text (page content). So, use the best keywords to make your Title as descriptive as possible. Let's say you have a music site with the URL "searchsheetmusic.com" Don't put "searchsheetmusic.com" in the title. A better Title might be: "Search Sheet Music: The Free Sheet Music Search Engine". This is much more informative and likely to generate better keyword phrases in the search engines: sheet music, free sheet music, sheet music search, music search, music search engine, sheet music search engine, search sheet music.