Depends what you have most are gimmics. However I like the battery one for laptops, recycle bin so you can keep your desktop free of icons, the control bar, which gives you easy access to all the on/off/hibernate/sleep buttons and of course weather.
Then a couple of gimmic ones just as I'm curious to what's happening on the network.
All depends what you want. some are very usefull. There's a great ebay one, if you use ebay loads.