... as for Snape, I always picture him as Maynard James Keenan of Tool
I haven't heard of Maynard James Keenan, so I Googled him, and found this picture. Have you read Pir8fancier's Snape, the Home Fries Nazi? Maynard looks very much like the Snape in that.
Non-book Potter fans have no idea, really, do they?