  The extragalactic distance scale relies heavily on Cepheids. However, it has
become clear from observations and pulsation models that the slope and zero
point of their P-L relations differ from galaxy to galaxy. This makes the
determination of Cepheid distances complex and calls for an independent test of
their differences. The test is provided by RR Lyrae star distances of 24
galaxies which calibrate the tip of the red-giant branch (TRGB; M_I = -4.05),
which in turn confirms the adopted Cepheids distances on our 2006 distance
scale in 18 cases to within 0.1 mag on average. Relative SN Ia and velocity
distances deny a remaining significant metallicity effect of the adopted
distances. The new support for these Cepheid distances increases the weight of
our previous calibration of the SN Ia luminosity and of the 21cm line width -
luminosity (TF) relation. The value of H_0 = 62.3 (+/-5) is confirmed on all
scales.
