As far as the Canon lens pouches go, they sit in the box they came in.
I no longer have any sigma lenses but I do buy the lowepro (or something similar) padded lens cases that are very like the Sigma ones. I have one to fit each of my lenses and use them whenever I'm backpacking/hiking/daytripping and I'm not bringing a dedicated camera bag with padding, which is becoming increasingly common.
I have a non-camera messenger bag to carry 2-3 lenses for more urban shooting, and in that situation I just use foam inserts as padding because the cases are too bulky.
Basically, I use the padded lens cases so I can fire them in a backpack that will have other non-camera stuff in it and not worry about having my lenses damaged. It just a slightly more disorganised camera bag!