Well we're starting to get some good gadgets for the Windows Vista Sidebar, which may force my hand and get me to actually use the Sidebar.

Windows Vista Sidebar Messenger gadget

I just found this gadget which hooks into Windows Live Messenger, and lets you see your contact list, without the wasted screen real estate of having the full client open.

You can download it from the gadget website. It's still pretty early, needs a bit more polish but other than that its a very functional gadget with a wide range of customizable options.