Amen. Backslashes are stupid. If you're one of the 0.2% of computer owners who know how and when to correctly use a backslash, you also already know that they have no business in a URL.

On a related note, I heard somewhere recently that one of the founders of the Web (I think it was Tim Berners Lee) came out and said "Um, about the two slashes in http URLs? Sorry about that. Turns out they weren't really doing anything important there." or something to that effect.