The additional information you requested: This is an ActionTec PK5000 DSL modem with 802.11b/g capability. It was set to automatically find the best channel, which typically was channel 11. I downloaded inSSIDer, and find that the modem is probably correct, but have hard-coded the channel to 1 as an experiment.
In the process of doing this, I noticed that WMM was enabled, apparently by default. I have disabled it, also as an experiment.
With inSSIDer, I find that my router is typically 30+dB stronger than any other signals in the vicinity.
I went to the Internet Services > Wireless Internet forum. I find that there are several reports of problems with Netflix and various Samsung TV's. Given the large number of posts on that forum, there were too many to manually sort through and the search is somewhat limited. Can you provide a couple links to threads that are examples of what you were discussing?
As to the issue with antenna differences between a laptop and a TV, I am somewhat at a loss. Given the relative sizes of a laptop and a 55" TV, and given that larger antennas typically perform better than smaller ones, the possibility that Samsung has not provided a good antenna for this TV only further suggests that I might not want to purchase a Samsung in the future.