I always think using "we" rather than "I" too. I don't know whether it's a hangover from when the kids were at home and I rarely went anywhere totally alone, or whether it's due to me talking to myself in my head. I mean, if I'm talking to myself, there has to be two of me, right?

I never thought it odd until I had a character do it in a story I wrote on the creative writing course the other year and my fellow students picked me up on it. Anyway, I'm glad hear that I'm not the only one who refers to herself as "we" in her inner monologues. :)