Facebook is a tricky one. We sorted out our page a bit on Saturday -
http://www.facebook.com/mattchedit - and have already won one (small) job from it.
I'd agree it's definitely best placed as a B2C tool - and would also venture so far as to say that it is going to work best if you have the sort of business where your personality/personalities shine through - rather than one which has a "corporate" front - if that makes sense.
The biggest mistake people make is in spending a lot of time adding content to Facebook, rather than using Facebook to draw attention to their content..!