$700 will not cover what you're looking to attain. a modest sub will chew up most of that. like your recording rig, you may want to buy your playback rig in stages. hang out in the playback area for a while to see what's going on, and to see if your budget is realistic. do you already have decent speakers? is this to be a multifunction playback system, surround and 2 channel? like pfife mentioned, if you don't need it, look at spending more on the components for 2 channel.
jr