First of all, good choice on BDP & speakers. My Marantz BD5004 has been the one constant in my hifi and AV. Brilliant and I'm sure the 7006 tops that, although not sure how 🙂. If the RX6s are anything like my RS6s they'll stand more than one amp upgrade and thank you for it too. Think you'll definitely keep them for a very long time. Regards connectivity I wouldn't go mad with HDMI cables although the very cheap ones in my experience do have suspect build quality Chord give good performance per pound on speaker cable, to even out your budget you can use some of the better quality for the front three. Chord Crimson sub cable or similar seems a quality but affordable solution for that cable too. One thing I would recommend is plugs on the speakers cables, it can get very fiddly around the back of an AV amp.