For a perfect website, length for Title Tag should be NOT more than 64 characters. It is because most of the Search Engines will takes first 64 characters, and generally appear on the top line of search results.
BUT, if your keywords are NOT there in the title tag, the site will not come up in search results. And, I noticed that many leading Web Design and SEO Companies do NOT follow the character limits, rather they go for longer title tags!!!
For example, a site that belongs to one of the leading website designers, comes up within the top 5 in the first page of google search, (PR of 5/10) has even more than 300 characters in its title tags….!!!
So, which is the right approach?