Facebook just opened its Open Graph protocol API which allows implementing social interactions in websites that were limited to Facebook pages only: likes, commenting, etc. The question rises if webmasters should bother to create Facebook pages anymore if their sites can be integrated in Facebook’s system.
The short answer they both serve a bit different purposes. Open Graph API helps people to connect themselves to brands. Facebook pages provide easier way on interacting with your fans. There is a much wider ecosystem of Facebook Applications than Open Graph applications at the moment.
Also, one needs to use FB application for managing and monitoring all the interactions through a website properly. Open graph insights are still a bit limited for my tastes, but I hope that new tools will emerge.
Also, Facebook pages help controlling brand mentions in SERP results, which might be important for reputation management. This can not be replaced by Open Graph API.
However, Open Graph shines with ability to help users quickly share recommendations and likes. It is easy to create Like button or Facebook comment box which pluggins that are already here. New tools will emerge that will aggregate and process user tastes. There are some examples already.
Overall, I would skip creating facebook pages under single condition: you will not have time nor content to represent your business in facebook. There are some websites that would not take too much use from community (for example, quick-help howto websites), but facebook page would not hurt anyways. On the other side, Open Graph might not be really useful in cases of existing Facebook page and little content on the website itself.