I think of 8x10" as my standard large-format format, but in the city, I'm really finding a niche for 4x5". It is no harder to carry than a 35mm SLR with a couple of lenses in a bag and a small tripod, and a folding viewing hood and more compact package are big advantages in dodgy areas where you might not want to be standing alone under a darkcloth or in crowds where there could be people wandering around who might just find some unattended piece of equipment interesting.

I'm almost ramped up to start using the 11x14". I've got some cheap outdated film on the way to experiment with and two S&S filmholders (that together cost more than the camera) on order.