The basic interface in Skyrim is aimed more at consoles than at the keyboard + mouse combo. Luckily, the modders took perfect care of this problem.
The SkyUI mod completely rebuilds and upgrades the inventory, magic, alchemy, enchanting, and smithing menus. In short - you can now use your mouse to navigate everything without any problems. Changes introduced by the mode include not only the interface but also the map, which now features a text-based search option.
The mod also changes some gameplay elements, adding the active effect icons on the screen. In the basic version of Skyrim you'd have to open the magic menu to check your active effects - now they can be seen anytime.
The entire interface is now much clearer and can be easily browsed - the mod allows sorting by name, type, weight, or e.g. price, and each item and spell has a separate type icon.
Note! The mod is available only for "standard" Skyrim.
The mod can be installed either using the Nexus Mod Manager or manually, by moving the mod files into the Data folder in the main game folder.
The mod requires Skyrim Script Extender to work properly. You can find an installer for this tool here.