I currently have an Onkyo TX-SR304 receiver and Polk M20 speakers. I have a feeling the receiver is better than the speakers so I'm looking to upgrade those. There are some used 15 year old Energy C5s in good condition available - is this worth a couple of hundred dollars to upgrade to? Alternatively are there are other speaker options I should try. It is mostly watching movies and listening to some streamed music (I have optical in to my receiver). I'm in Canada and assume my budget is low (ie. $400 absolute max).