I wanted to add UTC to my applet to make it easier to participate in Ubuntu Open Week (everything is scheduled in UTC). I'll explain the list of steps it took me to figure this out.

I can't find a way to select UTC, but I think its the same as Greenwich Mean Time but Greenwich isn't in the list of cities to select. So thinking thats in England I try to find a city in England, its not in the list, Maybe it Brittan, not in the list, Maybe its "Great Brittan", not in the list. After going to Wikipedia I find "...Royal Observatory, Greenwich in London...". London is in the list of locations in the applet. I now have London as a location, which I think is the right time.

In summary, instead of requiring the user to select a city, I think the timezone drop down should include real timezones, or at least allow me to type UTC in the "Timezone" field and press OK. Someone on brainstorm mentioned that by selecting London, I still don't have a UTC clock because they observe Daylight Savings Time.

Other information:
I filed this on Ubuntu Brainstorm, but figured I should send it upstream too.
http://brainstorm.ubuntu.com/idea/7983/