Or so is the title of the interesting post by Mike Bird over on Euangelion.
Reading his post, I thought of a book I've recently been reading, The Early Centuries: Jewish Believers in Jesus (amazon.com) by Oskar Skarsaune and Reidar Hvalvik. I've only read the introductory essay, but it's really prompted me to think about the spectrum between Jews and Christians in the early Christian Era.
The most intriguing insight, for me, was that there weren't just two flavors, "Christian" and "Jew". There definitely were "Christians" and "Jews", but there were also Jews moving toward Christianity (what the book calls "Jewish Believers") and Christians being influenced by and moving toward Judaism (what are typically called "judaizers"). Sort of like this quick diagram I made up:

Of course, there are other influences—don't even get me started on gnosticism—but the idea of thinking about the movement between these two poles and thinking about where, on this particular spectrum, different examples from different early writings could be plotted, causes me to think now when I read or notice Jewish-sounding influence in Christian writings.
Skarsaune & Hvalvik's book (amazon.com) should be interesting the more I get into it.