I do carry a few other bags, 3 others really. My huge Devi Kroell python when it rains, and I have a no-name bag from a lovely small french designer that I carry when I casually go out at night, so I don't have to worry at all about where I put it down. Finally, I have a brown Bottega Veneta Cabat that I really enjoy carrying as a more casual alternative to some of my Hermes pieces.
So those are pieces that I alternate with my Hermes because there are certainly days/occassions when I can't carry an Hermes for some reason. However, I still mainly carry Hermes, because as was stated previously, I also got rid of most of my other bags when I fell in love with Hermes!