In a post a while ago, I mentioned GeekTool. There are Widgets that can do everything that GeekTool can do, but they look pretty. The Widgets can take full advantage of Apple's Quartz rendering engine, so things can look very nice.
Here is a screen shot of my desktop now. In the lower left corner, I replaced the calendar from GeekTool with the built in Widget from Konfabulator. In the lower right had side, have the CPU Portal widget. On the left hand side, is the Picture Frame widget, iterating throught the pictures in my iPhoto library.