Mr Rid
Profesor Pixel Poo
I used the the old, forgotten 5D smoke plugin for this cigarette smoke in a shot for Sin City. Can be buggy, is not too versatile, but small wisps like this is the only practical use I've ever found for it.
http://www.box.net/shared/static/urr75v70id.mov
http://www.box.net/shared/static/urr75v70id.mov