if you aren't using 24-hour time, why?
really, it's fantastic
easier to do math with, better across timezones, and simple to use at a glance
no more "7 in the morning, or 7 at night?", just 7 or 19...
In Brazil, we use the 24-hour standard, and it's very practical. But for a wristwatch for example, even a digital one, I think the 12-hour standard is more comfortable
1