  This study combines data from a set of seven Cepheid-calibrated galaxies in
Virgo, Leo I and Fornax and four supernovae with known metallicities, including
metallicity corrections to the Cepheid distances, in order to determine a
consistent mean value for the Hubble constant. We derive Virgo and Coma
distances over different paths, starting from the metallicity corrected Cepheid
distances of Virgo and Leo I galaxies, and we relate them to the Virgo and the
Coma recession velocities, paying special attention to thereby introduced
correlations. We also determine the velocity of the Fornax cluster and relate
this velocity to its distance. In addition we use the standard constant maximum
brightness SN Ia method, as well as results from multicolor light curve shape
(MLCS) analysis of SNe Ia, to derive the Hubble constant. Using the requirement
of statistical consistency, our data set determines the value of the
metallicity coefficient (the change in magnitude per factor of ten in metal
abundance) to be 0.31 (+0.15/-0.14) in good agreement with other known
determinations. We also use consistency as a criterion to select between
mutually exclusive data sets, such as the two known, but conflicting, Virgo
recession velocities (in favor of the lower value), as well as between two
different analyses of (partly) the same supernovae (in favor of MLCS analysis).
When combining data we pay attention to the statistically correct handling of
common errors. Our result is a Hubble constant with the value H_0 = 68 +- 5
km/s/Mpc.
