This is a bit of silliness you won’t see often here. Skip it if you’re in a serious mood. Don’t skip it if what you are serious about is typesetting.
I dropped the double-space habit years ago and am firmly in the one-space camp (no rocket ships). I’m so firmly in that camp that when I co-author papers, grant proposals, and other writing endeavors I frequently edit out all those extra spaces that the two-spacers think are required (global find/replace makes this trivial).
Maybe you weren’t even aware of this debate. Wikipedia has lengthy entry on the subject.
The use of a single space after the concluding punctuation of a sentence is the modern convention for professional typesetting, final, and published work (e.g. books, journals, and periodicals). The use of a double space after a sentence has reversed nearly completely, primarily because of the widespread use of proportional fonts.
What’s your opinion? Are you in the we-are-right-dammit-one-space-camp or the if-it-was-good-enough-for-grandpa-two-space-group?