Further FYI, I have installed 35' HDMI runs that did not need amplification. I used a a beefier cable for that run, though.
For RCA cables: I try to use shielded RG59 or RG6 coax with crimp ends if the run is longer than 20' or so (usually a subwoofer run). For a video run, I always get the shielded bundles of three conductor (both Belden and Canare make nice cables for this). The longest I have tested was a 50' run of the Belden for component video + audio (5 conductors) and it surprised me how clear it was. No noise picked up at all.
For fiber, you could probably do a 250' run without too much problem
We routinely do 100' of standard multi-mode at work with no signal loss. Toslink (digital audio) should be comparable in terms of loss and signal strength.
Good luck.
For RCA cables: I try to use shielded RG59 or RG6 coax with crimp ends if the run is longer than 20' or so (usually a subwoofer run). For a video run, I always get the shielded bundles of three conductor (both Belden and Canare make nice cables for this). The longest I have tested was a 50' run of the Belden for component video + audio (5 conductors) and it surprised me how clear it was. No noise picked up at all.
For fiber, you could probably do a 250' run without too much problem
Good luck.