Not to start you guys fighting again, but I tune cars for a job, and when someone comes in and tells you that their CD player is broken, it is pretty easy to tell whether or not they are heavy smokers after pulling the deck out of the dash. The buttons do get this really gross **** stuck all around them, and sometimes it is enough to make bitchy car audio components stop working. I think it is up to the person whether or not they want to smoke in their studio, and most professional production is probably built strongly enough to handle it, but I would still never think of smoking in my studio. You should find to people who live close together with a similar piece of gear and do a head to head. Not scientific, but it would hopefully inform us a little better.
-Peasant Nikon