I completely understand where you are coming from , I am just not sure that you can get what you want for $500. I would stay away from older onkyo's which have proven problematic. For 2 channel I would understand not wanting to cross over to the sub but for home theater I see no reason not too. I would look at Denon or Marantz if it were me. I have a Denon 3311 and it is quite capable power wise and has preouts if you want to add an amp at a later date. It seems more and more that the addons are more important than the amplifier or preamp section.
