This is my inprogress HT/Music system. This is used for 50% 2 channel music, 25% multi-channel music, 25% DVDs.

Looking for advice on possibly upgrading speaker cables and any other suggested improvements. The rears will have to be 50ft and 30ft. Is it OK to use different kinds of speaker cables for rears, as that could get very expensive.

The sub will also be replaced eventually.

I don't play very loud; the room is about 20'x40', but the main listening area is 20'x20'. The height is 22'.