"In the current climate" - since the beginning of the recession this is the favourite line of people who like to look intelligent and know what is going on in economics.
"At the end of the day" - favourite of football players
"I was like [noise] and he was like [noise]" - try using some words, did this come from Friends?
"Awesome!"
"Epic!"
"Veritable smorgasbord" - only time you hear the word veritable, which is strange for a useful word like that.
"Eclectic" - used by poncy media studies students trying to sound smart.
"Je ne c'est quoi" (spelling?) - very ironic that this phrase is used by pretentious people and it means "I don't know what"
"Pretentious" - I use it all the time because I'm hypocritical.
Not overused words but overused mistakes: "Too" spelt "to", "you're" spelt "your" and "their", "they're" and "there" all mixed up. It's not that hard to learn which is the right one to use.