So, when he's praising the horns line, the piano line, or the complex electronic effects, it's not Kanye who's responsible for all of that, it's Daft Punk, it's Mike Dean, or Mohawke.
Anyway, I'm getting unnecessarily off-topic here. So to get back: Lou Reed was undeniably an innovator like no other, a true hacker. He knew how to play a mean guitar (jazz, blues, rock'n'roll and a whole lot else), he wrote great poetry. The greatest thing that's said about him is, indeed, as another commenter already has said: "Only about 3000 people bought Velvet Underground albums, but all of them started a band."
My two favorite songs of his: http://www.youtube.com/watch?v=ffr0opfm6I4 and http://www.youtube.com/watch?v=4wNknGIKkoA