I’ve long been a fan of limiting Facebook to personal interactions, although I have many friends with fan pages and am not promising that I won’t ever have one.
It’s a question of what kind of business you are representing and what you can do for people on Facebook that you can’t with a dedicated website. It takes some research and deliberation, but the cost is reasonable (free!) and that’s hard to argue.
This article cites quality research and makes some interesting points regarding perceptions involved with Facebook marketing. I