I haven't had cable television since the mid-90s. At the time, I was paying $40 or so a month and only watching 3-4 of the channels offered. I liked the Discovery Channel, I liked the History Channel, and I liked Comedy Central, but I'd rather be eaten by army ants than have to watch the Golf Channel, HGTV, or TBS. The way cable television works, it's like going to a cafeteria and having to pay for every single entree on the line when you're only going to eat a few things.
My dad has his digital satellite, and he's got the same story. $60 a month, and he'll never watch MTV or MTV2. He'll never watch VH1 or BET -- but he pays for them because he loves his ESPN channels. He's got 30 channels of music that he never touches.
I'd be happy to pay for television by the channel. Charge me a certain fee per month for the channels I want -- Animal Planet, Discovery, History, National Geographic Channel, Comedy Central -- hell, make me even HAVE to pay for my local network affiliates just to keep them happy, that would be fair if I didn't have to waste time with Spike TV or Fox News.
Ultimately, this will never happen, though. Small niche channels could never survive in a freedom of choice atmosphere -- but they can survive when thrown in with the big boys that everybody wants. Hmmm...the Social Darwinsim of cable TV? Might be an interesting process. Just don't make me watch E!