Somewhere on the Bethesda forums a poster noticed this, too. As for the music you have to remember that Fallout 3 is based on the 1950's versions of the future. To me, it therefore makes sense that the music used is from the 1950's in the game. This means there have been no hiphop, no breakdance, no house or dance music. Only the 1950's music - like a place frozen in time.
Oh, I know it is a tribute to the setting of the originals. My problem with the 5 movie clips was, that it was the only thing "50'es" about them. The had that retro "90'es" feel to it (hence the S.T.A.L.K.E.R. reference)