Your best categories in a simple tabs widget (Jquery UI Tabs).
Simple plugin that allows you to generate a tab container widget based on Jquery UI tabs. Each tab is a category with a number of posts customizable. It will display last posts of your favorite categories just put each category ID number separated by comma.
All other information (general, changelog, installation, upgrade, usage) you need about this plugin can be found here actually in italian: Post2tabs readme.