Also Guilds provide you with the recipes to craft legendary items later on. Like Weaponsmith Guild members can craft legendary swords+axes, while Woodworker Guild provides legendary bows, crossbows and spears (just to provide a few examples). So if you want to make your own legendary items after Moria you may want to join the guild that gives your class-specific LI recipes.
Used to play: 85 Champ / Captain / Runekeeper / Guardian, Guild Master of everything but cooking.
Playing now: Hellcat / King Tiger / GW Panther / IS / KV-5 / M4 Sherman and more