"At the end of the day" was the most over-used cliche in British newspapers and websites between January and June 2006 , according to a new survey by Business news and information provider Factiva. There were 3,347 mentions, closely followed by "in the red" and "level playing field". The research found that financial turns of phrase were most popular, a pattern followed in most of the world's English speaking press. Biggest surprise though was the absence of "looks like a librarian" - must be a mistake. And if the survey was restricted to the library/ information management media, I'm sure that "thinking outside the box" would feature highly.
Here's an index of cliches with a slight US bias, where you can summon up a cliche quicker than shit goes through a goose.