Keep in mind that it's not just a matter of impedance. A balun provides a balanced circuit for the signal's long haul, something that can better handle unshielded twisted pair, nomatter the distance. You still might be able to use standard a/v cables for 60-ish feet, provided they're well made (like Bluejeans' stuff).
Having said that, I use the Muxlab digital audio baluns (purchased from Hometech) on a 45-foot run of cat 5 to get from a PC w/M-Audio Sonica Theater in the basement to the HT receiver in the family room. It works great with one exception. I have an old Proceed DA that does not like being fed by that line. It can't sync up. But my Denon 3805 and M-Audio CO3 like it just fine.
As for analog A/V, I haven't tried any baluns yet, but I'm considering one for s-video and stereo audio (to feed the output of a sat receiver to other areas). Take note of the specs. I noticed on the analog audio balun from Muxlab that the 3dB rolloff points are 60Hz - 20kHz for less than 1,000ft of cable. That's an octave and a half off the bottom. And it's 100Hz - 20kHz for over 1,000ft. More than 2 octaves. I suspect most household applications won't involve runs over 100-150 feet, though. Plus I'm talking about the output of a sat receiver going to a 13" TV in my wife's sewing room.
Just be sure you check the specs. I think that these baluns are fine for "zone 2" applications, but perhaps not for critical listening and viewing.
