I have a Sony HT-DDW740 HTiB. I need opinions on whether I should upgrade the speakers. I like the sound as it is, but I can get the Onkyo HT-500 speaker set which I hear is awesome. My question is this: Would I get noticably better sound with the Onkyo ($270 better) or is what I have close to that level? Anyone have experience with both? How good is this Sony anyway? Ok so that was 3 questions... Sue me.