  We identify a correlation space involving optical and UV emission line
parameters as well as the soft X-ray spectral index that provides optimal
discrimination between all principal classes of active galactic nuclei. Most of
the sources in our three high quality data samples show a strong
intercorrelation with narrow line Seyfert 1 (NLSy1) galaxies and steep spectrum
radio galaxies occupying opposite extrema in the space. NLSy1 sources show a
clear continuity with broader line sources indicating that they are not a
disjoint class of AGN as is sometimes suggested. We interpret the principal
intercorrelation in the parameter space as being driven by AGN luminosity to
black hole mass ratio (L/M prop. to the Eddington ratio). Source orientation no
doubt also plays an important role but it is not yet clear whether FWHM H beta
or CIV 1549 line shift is the better indicator. We tentatively identify two RQ
populations: an almost pure RQ population A with FWHM<=4000 and population B
which occupies the same parameter domain as the flat spectrum RL sources. A
possible interpretation sees Pop. A/NLSy1 as lower mass/high accretion rate
sources and Pop. B/RL sources the opposite.
