  We report on our recent study of equilibrium thermodynamic observables in
SU(N) gauge theories with N=3, 4, 5, 6 and 8 colors at temperatures T in the
range from 0.8 T_c to 3.4 T_c (where T_c denotes the critical deconfinement
temperature). The results, which show a very weak dependence on the number of
colors, are compared with gauge/gravity models of the QCD plasma, including the
improved holographic QCD model proposed by Kiritsis and collaborators, and with
the supergravity prediction for the entropy density deficit. Furthermore, we
investigate the possibility that the trace anomaly may receive contributions
proportional to T^2 at temperatures close to T_c. Finally, we present the
extrapolated results for the pressure, trace anomaly, energy and entropy
densities in the limit for N going to infinity.
