  We construct new galaxy angular power spectra based on the extended, updated
and final SDSS II Luminous Red Galaxy (LRG) photometric redshift survey: MegaZ
DR7. Encapsulating 7746 deg^{2} we utilise 723,556 photometrically determined
LRGs between 0.45 < z < 0.65 in a 3.3 (Gpc h^{-1})^3 spherical harmonic
analysis of the galaxy distribution. By combining four photometric redshift
bins we find preliminary parameter constraints of f_{b} = \Omega_{b}/\Omega_{m}
= 0.173 +/- 0.046 and \Omega_{m} = 0.260 +/- 0.035 assuming H_{0} = 75 km
s^{-1} Mpc^{-1}, n_{s}=1 and \Omega_{k} = 0. These limits are consistent with
the CMB and the previous data release (DR4). The C_{\ell} are sensitive to
redshift space distortions and therefore we also recast our constraints into a
measurement of \beta ~ \Omega_{m}^{0.55}/b in different redshift shells. The
robustness of these power spectra with respect to a number of potential
systematics such as extinction, photometric redshift and ANNz training set
extrapolation are examined. The latter includes a cosmological comparison of
available photometric redshift estimation codes where we find excellent
agreement between template and empirical estimation methods. MegaZ DR7
represents a methodological prototype to next generation surveys such as the
Dark Energy Survey (DES) and, furthermore, is a photometric precursor to the
spectroscopic BOSS survey. Our galaxy catalogue and all power spectra data can
be found at http://zuserver2.star.ucl.ac.uk/~sat/MegaZ/MegaZDR7.tar.gz.
