The UN46C6900 is a Best Buy exclusive, and doesn't have the SamsungApps, but does have HotApps, which is a partnership with Best Buy for many of their widgets. You'll still be able to get Netflix, Pandora and many of the other services, but they won't be under the SamsungApps, but the HotApps offering by Best Buy.
Currently, there are no plans to release a B8500-like LED for 2010 that I'm aware of. Things can change, of course, but at this point, I'm not aware of any plans.
Does that help?
I have been interested in purchasing the UN46C6800 for quite some time now and then today noticed there is a UN46C6900. What is the difference? This TV will be used in a room that could be quite bright during the day (several windows) but most of the viewing will be during the evening. Is this a good choice? Does Samsung have anything comparable to the 2009 UN46B8500 for 2010? I appreciate your time and help!