By most accounts, clubs in New York City are back to the same level of business they enjoyed before the city enacted its smoking ban. This shows me even more that when bans like this get introduced in other cities, nervous club owners use them as an easy out to shut down or move out of town. It takes a lot of guts to run a venue -- most are low-margin, high-stress operations. And any preceived threat to business can make a club owner fell like they've got to leap off the cliff.
Even though a new smoking ban in your town shakes out "the scene" and leaves fewer stages to play on, remember the kinds of opportunities it creates: more private membership clubs, house concerts and alternative venues. You may need to go under the radar to find these outlets for your music, but you'll find warmer audiences. And when you do play clubs, you won't have to get scrubbed down by hazmat teams the next morning!