Maybe a better way to ask SaigonK's question is If you have cable modem and 2 TVs, where is the best place to split the line? I dont' have a cable TV box or line filter to deal with.
As I see it, there are 2 options:
1) 3-way splitter to Modem, TV-1, TV-2
2) 2-way splitter to Modem and then to...