When my logitech g27 racing wheel was still working i USED to play the living hell out of modded richard burns rally it was fun playing a racing sim with almost life like physics.
Best rally Sim is definitely debatable, but it most definitely still holds up pretty well against more modern rally sims like Dirt Rally 2.0, and that is insane enough considering it's age. The mods for RBR have definitely extended its lifespan.
The physics in RBR still feel better to me than the modern rally games like Dirt Rally 2, and WRC9 and what not, and that is incredibly impressive. I will say the modern games are better for competitive play and obviously have better graphics and immersion.