Everyone's answer will be different, because of your own personal aesthetic, vision for your blog and the type of blog you're building. However, there are five widgets you must have in your sidebar to be effective.
- Your About Me Widget
- Your RSS Link and Subscriber Count
- Newsletter and Email Subscription Links
- Top Place to Find You Online(Twitter or Facebook)
- Book Review Links List
- Book Review Submission Form or if you're an author your Bookings Request Submission Form
- Your Phone or Skype Number