Hey FJames - snap!!!
Yep, I carry lots of electronic gadgets in padded clear plastic postal envelopes as well!!! And the best part is that I get them from my local Post Office for a maximum of $2 or $3!!! Wow, unbeatable price and absolute value for money. They last and last and last!!
However I sometimes still use the protective case that the gadget came with and place them in the bubble plastic envelope when I put them in my day pack, because I also carry water and my lunch and fruit etc in the pack. So that way I'm sure that no fluids or sticky stuff will get on my gadgets.
Also excellent for traveling - I put my lap top in a large plastic bubble envelope in the middle of my clothing in my large traveling suitcase, and never had any probs.