Aura Whisper
Your Voice is not a Shout, but a whisper, revealing the life forces of any and all. Words: LAAS (Life), YAH (Seek), NIR (Hunt) Aura Whisper basically acts as a more powerful form of the Detect Life spell, the extra power being that it also detects the auras of machines, Daedric creatures and undead. LAAS alone will give you ten seconds time in Aura Whisper mode but each learned word on top provides an extra ten seconds.
Uses: There are plenty of quests that encourage you to use stealth (the thieves guild quest chain for example, which is worth doing even without specialisation in the appropriate skills). If you havent put the feats into your stealth tree then these quests can often be extremely difficult to complete. Detect Life in general is basically a stealth tool; you want to see where the enemies are ahead of time so you can plan your route accordingly. Aura Whisper is ideal for anyone specialising in being sneaky; its nigh on essential for anyone who isnt but still wants to remain undetected.
Where to Learn (in order of power): LAAS
Northwind Summit YAH
Valthume NIR -
Volunruud