I just picked up an Onkyo sr606 after reading many posts on here. It seems like the SR606 is a little future proof and it seems to have all the features that I would need. I guess this is a middle to low end receiver as far as receivers/price goes. What do I get with a higher end receiver? What am I missing with the SR606. Is it sound quality or is it more features / bells and whistles. If it is only sound quality I think I am more than satisfied with the sound I get from the SR606. If it is features.. what are they. Convince me that my SR606 is not good enough.