What Blog Widgets Do You Like?

I admit it. The next biggest step in getting my sites squared away is unifying the blog widgets as best as I can, but I'm stumbling about a little knowing what to use. I like Plurk's concept, but the widget is as big as a loaf of bread compared to others. Technorati has a ton of options I really need to explore. ShareThis will be key, I'm sure. But what sort of widgets are you using, and what has provided you the most success? What has really defied your attempts to make it work, and what do you think is the reason why?