I just ordered a one of these:
http://white-noise.us/screen580_980.htm
I call it a sound machine, my father (a psychiatrist) had a couple in his waiting room while I worked in his office, but I guess a more accurate name is a white-noise sound screen. The walls in my office are paper thin so it's high time SOMEONE did something, might as well be me.
I wouldn't think it would work to cut through "serious" noise like from a rockin' restaurant and bar, but if a floor fan works then this certainly would. It makes a whooshing "schhhhhhh" sound that people don't notice if it's already going when they walk in.
Sounds like a great location for getting business! Congrats!