As part of the ARCHES European FP7 collaboration work, we combine FIRST and NVSS with a new technique, cross-correlating the result with the WISE and 3XMM catalogues. With this radio selection we obtain a large, clean sample of radio-loud AGN across a wide range of luminosities, as well as a smaller sample of nearby star-forming galaxies. Free from the constraints of traditional X-ray and mid-IR selection cuts, we study faint AGN in systems where the host dominates the emission, and draw better constraints on the luminosity relations for AGN and star formation activity. We also explore the relation, or lack thereof, between radiative output and jet kinetic power in AGN, which is key to our understanding of accretion, discussing its implications on regulating mechanisms for the jet, and long-term variability timescales.