Well done on giving up the fags, Satch!  (Cue giggles from our American Chums...)
I have a ciggie pack sized Innokin AIO, so it just goes wherever I used to carry my smokes.   I'm about to get an eGo Twist battery, though, so I will have to think about carrying arrangements myself.   Thinking about an eGo case, so I can also chuck a few spare bottles in there too.  I usually carry a small messenger bag with me when I'm out and about though, so it would just be to keep everything organised within that really.