Well, I will make a visually entertaining guide once I have some Dungeons and Bosses that I can put in here.
For now, glorify yourself in this boring, short guide that will be updated over time, until the visual one is inserted.

Dungeons:
name - location - recommended level - Boss - quests - rare treasures

Northerend Shrine - Northerend Forest North - 8 - TBA - n/a yet - TBA


Bosses:
name - location - level - quest - drops

Yuzkrow - Skyhall Castle - 55 - n/a yet - TBA
Yulan - Skyhall Castle - 60 - n/a yet - TBA (note - defeating him is one of the several pinnacle moments in the story that is classed as "Completing the Game" - this one is "Defeat the Final Boss in the Main Story")