blackhawk is pretty right on. lots of people are having trouble getting a good setup with the equipment that they have currently only because they either don't know how to set it up correctly (which can definitely be a pain) or end up using cables which dampen the quality.
if you can, take some time into reading up on the equipment that you have, you may find someone who has something similar if not identical and from there you can gauge if its a good idea. sometimes you might have to upgrade different components, but i wouldn't look too far ahead just yet.
i've found a few good reviews at http://www.avreceiverreviews.com/
which has lots of people talking about different types of setups. you don't have to have a uniform setup to always have the best sound, thats just what a lot of companies want you to believe.