I have been looking for a clock app that displays multiple clocks on my desktop, for different time zones. When I travel, I leave my MBP on my home time so as not to mess up my calendar, and I want to be able to display one or more clocks with the times in the places I'm visiting. Clox fits the bill.
Clox works as described, works well with Spaces on 10.6 (which isn't the case with some of the other clock apps I've tried), and there's no dock icon. I can adjust the transparency of each clock, and set clocks to remain n top of other windows, with the ability to click through the clocks, so I don't lose any screen real estate (moving a clock requires disabling the click-through feature first).
While the various analog clock styles are good, the one thing about Clox I don't like is the digital clock styles, which are all really tacky and/or juvenile. Clox would get five stars if the dev added a few good digital styles, like a flip clock, a HUD style clock, an old school LED clock, that sort of thing.