AideRSS is more than just a top posts widget. AideRSS is actually a way to sort through a lot of the noise by filtering out posts by different levels based on your interests. For example you might not want to read every single post Boing Boing posts. Using AideRSS you can subscribe in your RSS reader to the best posts that they create, thus eliminating some of the noise that can clog up your RSS reader.
The side benefit of AideRSS is that they create top posts widgets. You can submit your own blogs RSS feed, such as your Blogger.com blog and AideRSS will create a top posts list sorted by what they call postrank. You can choose the time period that you want the top posts to be created from. Either year, month, week or day, and the number of top posts you would like to show. Here is a sample of Epibloggers top posts widget showing the top five posts for the year.