The thing about DLC, for me, is that its always been about the gear and extras you get. I didn't really care for any of the scenarios in the FO3 DLC's with maybe the exception to The Pitt. But Zeta, Broken Steel, Anchorage and Lookout all were kinda blah.
The bulk of my enjoyment came from starting out small time and getting stronger level wise and gear wise and in that sense the main game is enough for me.