Hi
I think there is definately a role for Facebook for small businesses, especially those that have a consumer product. 500 million people are on there...it is worth thinking about! My views below for what they are worth.
I personally think the key is setting up a Facebook page (used to be known as a fan page) for your business, and ensuring you keep it up-to-date with interesting content and find ways to encourage people to "Like" it.
Ideally interesting content means a mix of info about your business and interesting/helpful articles that your audience who "like" your page want to see. Try mixing it up with articles and also video.
I don't know what your business is, but as an eg I am helping a client with her beauty business, she uses her Facebook page to; promote offers that she is running, promote competitons (which are a good way of increasing visability on FB), share links about latest beauty treatments, styles and beauty press articles (not all of which feature the type of services she offers), links to the company that provides her products and then a peppering of more "personal comments" about running her business, eg "Just spray tanned a bride for her big day on Saturday, she told me about her dress, it sounds amazing".
I do think it is worth/important having a business page to output your business info, as even if you are happy to use your personal page to talk about your business, most people use their own pages/accounts for personal stuff, so might not like/be used to one of their "friends" doing that...
You can also control the content, so if somebody does post something unpleasant you can remove.
The best place to start, which it sounds like you are doing, is to set your self us as a user, and "like" other businesses pages (especially those in the same industry as yours) and see what they do.
Good luck!
WS