Mine didn't feel very creative at the time...but I am glad I chose it.
I am a cat lover, with two cats of my own, and I currently live with three more (yes, I live with a total of five cats). On of my kitties is named Matilda the Russian Spy (my other cat is Secret Agent Sam). Matilda is a very fluffy itty-bitty-kitty, and from the back she looks like she is wearing pantaloons.
Her nickname is Matilda Pants, or Miss Pants, or a thousand variations of that.
SO...I am MatildaPants, because she would cache if she could, and she is always with me on the computer. Like I said, not very creative, but there it is.
MatildaPants FTW!