This is not a simple answer, as our product is very robust, allowing you to do many different things. The best widget to use depends on what you're trying to add. The following are the top widgets we recommend for use, but we also encourage you to poke around and play with things - just be careful with the delete button. :) Deleted widgets are non-recoverable.
When all you are looking to do is add some simple text, for example, "Our Care Center is open 24-7, 365 for all of your healthcare needs", the best widget to use is called Text.
If you're needing to add complex text, such as internal, external and/or PDF links, or an image, the best widget to use is Black Studio TinyMCE.
When you want to add a menu to the sidebar, the best widget to use is Custom Menu. Just remember to have already created the menu in Appearance > Menus, otherwise the menu name will not show up in the dropdown list in the widget.
When you're wanting to add a list of events to your sidebar, the best widget to use is Events List. Of course the events should already exist in the Events area before you attempt to display them in a sidebar. You can customize the displayed content by past, upcoming or all events, by event category and the number of events you want displayed.
Recent blog posts are seamlessly added to a sidebar by using the Recent Posts widget. You can easily select how many you want to display and whether the post's date shows or not.