Nice Menus and Superfish modules allow you to create vertical and horizontal dropdown menus. You should choose one of the two and use it. Both modules are popular and have many add-ons.

Both Nice Menus and Superfish use the same jQuery Superfish library:

FileField provides a universal file upload field for CCK.
It is a reliable alternative to the core upload module and an essential tool for users uploading large numbers of files. It is particularly well-suited for managing video and audio files, such as podcast content on your site.

Features:

The Pathauto module automatically generates URL/path aliases for various types of content (nodes, taxonomy terms, users) without requiring the user to manually enter the path alias. This allows you to have clean, user-friendly URLs like /category/my-node-title instead of /node/123. The aliases are based on patterns that use tokens, which can be customized by the administrator.

Taxonomy or taxonomic schemes consist of taxonomic units known as taxa or types of things, which are often arranged in a hierarchical structure—typically based on subtype-supertype (parent-child) relationships. In such subtype-supertype relationships, a subtype inherits all constraints of its supertype, plus one or more additional constraints. For example, a car is a subtype of a vehicle. Therefore, every car is also a vehicle, but not every vehicle is a car. A car must satisfy additional requirements beyond being just a vehicle.

Tokens are small pieces of text that can be placed into larger documents through simple placeholders like %site-name or [user]. The Token module provides a centralized API for modules that use these tokens, and it also allows you to define your own token values.

Note that the Token module itself does not provide any user-facing features. It only offers token handling services to other modules.

ImageField provides image upload capability to a CCK field. Based on CCK, ImageField is an alternative to legacy image handling tools. It offers features like multiple images per node, resolution constraints, default images, and enhanced support for Views.

ImageField does not provide built-in thumbnail generation but complements the incredibly powerful image generation module ImageCache.

ImageField is associated with:

ImageCache has been moved into the core in Drupal 7. ImageCache allows you to set presets for image processing. If an ImageCache derivative doesn’t exist, a server rewrite rule passes the request to Drupal, which in turn forwards it to ImageCache for dynamic file generation.

ImageCache requires that you:

This API interface is intended as a replacement for the image APIs provided by image.inc. You do not need to install this module unless another module requires it. It does not add new features to your Drupal site — it only provides an API that other modules can use. Currently, GD2 and ImageMagick are supported and bundled with ImageAPI.

Note: Requires PHP5!

Differences from Drupal core’s image.inc:

This package provides a flexible Date/Time field, similar to the Date field and Date API used by other modules.
For Drupal versions 5 and 6, the Date field requires a set of CCK modules. In Drupal 7 core, it works by default.

Most of the Calendar module’s functionality comes from the Date module. Therefore, whenever you update the Calendar module, make sure you also update the Date module to the latest version.

In this section I will collect articles that do not fit into existing sections, but are very interesting.