Like your logo it is important to keep your image the same across all profiles so you are easily recognisable. Familiarity builds trust and so you need to make your customers feel comfortable when they meet you, not have them thinking you have something to hide.
No need to panic though! Facebook will still support Fanpages already using FBML code. It will only affect Fanpages wanting to create a custom page from 2011. Here's an excerpt from Facebook Developers list of changes expected in the first quarter for 2011