Julio Potier

IMPORTANT: 3.0 supports cahing plugins!
When someone visits a post or page (not a search engine bot crawler), it adds 1 count views to its counter.
But this is not all, the counters are split in days, weeks, months, years, so you can see stats and display any stat day.
Then you can display this views with the provided shortcode [post_view] or use the widget to display a top (or less) posts list.
You can also use [most_view] in a post/page to get a top (or less) post most viewed.
If you were using another kind of plugin before and don’t want to lose your counters, this plugin can keep them!

Post Views Count (Support caching plugins!)

This plugin counts views for post and pages, shortcodes [post_view] & [most_view] are available, also a widget "Most Viewed Posts" is.

maxpagels

Most Popular Tags is a WordPress plugin that allows you to display your blog’s most popular tags or categories as a sidebar widget. The plugin takes advantage of the new Widget API introduced in WordPress 2.8, allowing multiple instances of the same widget, each with it’s own unique configuration. You can specify how many tags/categories/link categories to show, the size of the smallest and largest ones, which unit and format to use as well as advanced ordering options.

Most Popular Tags

Most Popular Tags is a plugin that displays your WordPress site's most popular tags, categories and custom taxonomies as a sidebar widget.

Post Views Count (Support caching plugins!) vs Most Popular Tags