"ONORE DECADE!!!!!!" and "THIS IS ALL DECADE'S FAULT!!!" -- Almost all the time when things go wrong. It's replaced my usual "Damn you, Murphy!" yell.
The rest are so obviously Den-O and Kabuto references...although I tend to say them in english, so...
"I am the man that stands at the top of screwing things up!"
"Mind if I string you along...?"
"I'm going to make you CRY!"
"Let me say this to start~!"
"Grandma once told me..."
But my current favorite is:
"Vampire...That life you took, return it to God!"
...it drives Twilight fangirls berserk. In the wrong way.