Install Leatrix Maps for a better world map and TomTom for a waypoint arrow. Those two cover most players. Add Shortest Path Forever if you'd like routes planned for you.

Add-on What it adds Best for
Leatrix Maps Coordinates, level ranges, a smaller movable map Nearly everyone
TomTom A waypoint arrow set with /way Following coordinates
Shortest Path Forever Directions using walking routes, flight paths, boats and portals Not planning trips by hand
Mapster Map scaling, transparency and coordinates An alternative to Leatrix Maps
Waypoint UI A marker inside the game world Keeping your eyes off the map
SexyMap Minimap shapes and button hiding A cleaner minimap
BasicMinimap A simple square minimap Keeping it plain

All of these listed a Forever version when we last checked, before launch. Each page shows its date.

Don't double up

Leatrix Maps and Mapster change the same map, so choose one. If the map starts behaving strangely, turn one off first.

Boats and zeppelins

Blizzard has confirmed that transports can get lost and added temporary portals near most docks. A route that relies on a boat may take longer than it looks until that's fixed.

Quest helpers are separate

These add-ons won't tell you where a quest objective is. For that, see best quest add-ons. For a guided route from 1 to 60, see Azeroth Pilot Reloaded.