Jonathan Coulton comes to mind.

I like simple things. His lyrics are intelligent, tend toward the uncomplicated, and his music typically features simple power trios.

  Hello from Sputnik 2
  I am receiving you
  Thanks for the dog food
  I'm somewhere above you now
  Guess what Malashenkov?
  I took the collar off
  I'm holding my own leash
  And walking myself outside
  This door
  I don't think
  I want to be a good dog anymore.

Plus, he licenses all his music Creative Commons. Yay Freedom of Information.

I also love Yuki Kajiura's songwriting. She writes for Kalafina, who primarily perform for anime series'. I looked up the lyrics for the Aldnoah Zero theme out of curiosity. The English translation left me breathless. Most of her songs are equally evocative.

  The dream you have 
  Is like a prayer in ink on parchment 
  The thing that your small hands cling onto 
  Does not yet exist 
  Even so I wish to protect 
  That road you will travel down 
  And to keep what's beautiful as beautiful
  …
  If there's anything you desire 
  I will stand by your side 
  And reach out towards the same horizon 
  Will I ever be able to reach 
  That silent sky that you believed in 
  That brilliance that went on forever 
  That heavenly blue
  (full translation)

For Hubski Anime Clubbers, she wrote the theme for Madoka Magica, too.