The Global Language Monitor publishes an annual list of top words, phrases, and names. I don't know how they come up with these lists. Are they the most spoken, most cited in the media, the most cited in American media, or something else? Also, it's clear from this list that they weren't very strict with their calculations--avian flu and bird flu were considered to be one phrase.
In any case, some interesting top-10s from 2005 include:
The Top Ten Words of 2005
In 2004, the Top Words words were incivility, Red States/Blue States, and Blogosphere.
- Chinglish (Chinese + English)
- recaille (word used to describe youthful French rioters of North African and Muslim descent)
- SMS (Short Message Service, a.k.a. text message)
The Top Ten Phrases of 2005
In 2004, the Top Phrases were Red States/Blue States, moral values, and Two Americas.
- out of the mainstream
- bird flu/avian flu
- politically correct
- North/South Divide
- purple finger/thumb (badge of honor worn by Iraqi voters proving that they voted in their ground-breaking elections)
- climate change/global warming
- string theory
- the Golden Quatrilateral (India's new superhighway system that links the key cities of the Subcontinent)
- jumping the couch (losing complete emotional control; made popular by the escapades of Tom Cruise on the Oprah television show)
- deferred success (idea introduced in the UK that there is no such thing as failure, only deferred success)
The Top Ten Names of 2005
In 2004, the Top Names were Dubya Rove (W. and Karl Rove), Mel (Gibson) (Michael) Moore, and Saddam Hussein.
- (Acts of) God
- John Paul II
- Wen Jiabao (Premier of the People's Republic of China since March 2003; leading perhaps the largest economic transformation in history)
- Saddham Hussein
- Shakira (Columbian songstress)
- John Roberts