Honestly, rather than have a lot of different clocks (clutter) I'd prefer one clock that would switch time zones easily

For example, the "wallpaper clock" would be much more useful if it had a row of buttons across the top labeled GMT EST MST CST PST as well as other popular european time zone abbreviations like CET and so on. If we run across a site with an odd time zone, instantly click the appropriate time zone to see how many hours changed. Hover the cursor over the time zone and perhaps it could show the difference in hours from our current time (i.e. +8 or -5).