Showing how many nodes are associated with a term
For relatively small vocabularies, it may be useful to create a block of terms that also shows how many nodes are associated with that term.
Create a view that shows Taxonomy terms (not Content) and select one particular vocabulary. You can create a block or a page, and you can choose any of the core Views formats (unformatted list, table, grid, etc.); just be sure to select fields as what is displayed.
In the full Views interface, toggle open the "Advanced" section, and under Relationships, add "Taxonomy terms: Content using [vocabulary name]". In the "Other" section within the "Advanced" section, click "no" next to "Use aggregation", and check the box for "Aggregate".
In the "Fields" section, add the field "Content: Nid" and choose the aggregation type "Count". Uncheck "Create a label". To make the node count appear next to the term name, in the "Format" section, click on the "Settings" next to "Fields" and check the boxes for the two fields you currently have in your view. To add parentheses around the node count, edit that field, toggle down "Rewrite results", check the box for "Rewrite the output of this field", and in the box that appears enter ([