I've always used one space. I knew the two-space style was out there but never really gave it much thought. Apparently this annoys my girlfriend, who was taught to use two spaces.
One area where I seem to find myself in the minority is my use of the Oxford comma. I was taught to use it, and it makes the most logical sense to me.
It sounds right to me. When reading the list you would pause momentarily at that point, so why not use a comma?