  We determine the contribution of stars in galaxies, intracluster stars, and
the intracluster medium to the total baryon budget in nearby galaxy clusters
and groups. We find that the baryon mass fraction (f_b) within r500 is constant
for systems with M500 between 6e13 and 1e15 Msun. Although f_b is lower than
the WMAP value, the shortfall is on the order of both the observational
systematic uncertainties and the depletion of baryons within r500 that is
predicted by simulations. The data therefore provide no compelling evidence for
undetected baryonic components, particularly any that vary in importance with
cluster mass. A unique feature of the current analysis is direct inclusion of
the contribution of intracluster light (ICL) in the baryon budget. The increase
in X-ray gas mass fraction with increasing total mass is entirely accounted for
by a decrease in the total stellar mass fraction, supporting the argument that
the behavior of both the stellar and X-ray gas components is dominated by a
decrease in star formation efficiency in more massive environments. Within just
the stellar component, the fraction of the total stellar luminosity in the BCG
and ICL decreases as velocity dispersion increases, suggesting that the BCG+ICL
component, and in particular the dominant ICL component, grows less efficiently
in higher mass environments. The degree to which this behavior arises from our
sample selection, which favored systems with central, giant elliptical
galaxies, remains unclear. A more robust result is the identification of low
mass groups with large BCG+ICL components, demonstrating that the creation of
intracluster stars does not require a massive cluster environment. Within r500
and r200, the BCG+ICL contributes on average 40% and 33% of the total stellar
light, respectively.
