Here is a sample of one I configured in around a minute and then bookmarked and shared:
I couldn't get a larger image to work well in this theme so to see this for yourself use this link.
It may not have the fanciest name or super sleek graphics, but its display of information is amazing. Above we see that:
- It displays current times clearly for all timezones I care about in an easy to read/compare way.
- Everything is vertically aligned with readable values for easy comparison
- I see whole-hour times for a 24 hour period
- I see current exact times
- I see offsets (+4, -6, etc) from my home time zone
- It shows the current date in each time zone in an easy to follow way
- It shows business hours, night hours, and late night hours in different colors
- It alerts me to upcoming time changes - in this case, Europe's daylight savings equivalent happens 4 days from now
- I can remove a timezone I no longer need with one mouseclick
- I can change my home timezone with one mouseclick
- Not visible in the above screenshot, but visible with the mouse cursor is the ability to drag and drop re-order timezones in any way I choose. I put mine in ascending order, but that isn't enforced, it was my preference.
- I can click link icon in the top right corner to get a link to the site containing my customizations, easily bookmarkable and shareable with coworkers.
- New timezones can be added by using an autocompletable field (just start typing a city or country name)
If you deal with multiple time zones a lot, definitely check out World Time Buddy.