My interconnects follow the same migratory pattern outlined in your message...initially from the source to the preamp-amp and then upstairs to the two-channel HT system. If they ultimately get bumped from the latter, they go to one of my three kids for their systems. Same with the speaker cables.
Do your Cables migrate thru your system?
I initially bought a pair of Audioquest Emerald ICs for my CD player/receiver setup (eons ago). Then I upgraded to separates and got a good deal on a run of Lapis from the CD to the pre-amp. The Emerald got demoted to the pre-amp/amp run. Then I found another run of Lapis to fill in from the pre-amp to amp. The Emerald got kicked out the system all together and demoted to home theater. Yes, I run Emerald for my front speakers. Bought the DVD player and got a run of Coral for free. This connects the rears. I bought a five-channel amp and got a run of Opal for free. One half connects the center channel. The other half...the sub. I've never bought a cable for home theater, I just used the fall-out from my audio system or got free stuff. Anyone else have a similar story?