Agreed. Cable has made television better than ever. Writers, directors and actors have found a medium to tell the stories that were previously reserved for feature films but has fallen out of favor because of the ridiculous cost of getting a small movie made.
Another thing that is better than ever is the miniseries. While we think of "Meteor!" and "10.5" cable, HBO specifically, is really showing what you can do with an epic story that would take too long to tell in cinema. Look at House of Saddam, Generation Kill, Elizabeth I and the grandaddy of all miniseries, Band of Brothers. The Pacific is coming next year to be the other grandaddy.
Along those same lines, television writers are learning that their 10-13 episode seasons of cable shows can play out like chapters in a novel, like The Wire, True Blood, Mad Men, The Tudors. There's a connection with literature too. True Blood and Dexter are based on book series. A Song of Ice and Fire is in development. The Wire went as far as attracting authors like Dennis Lehane (Gone Baby Bone, Mystic River) to write episodes and consult. Adaptations provide seasons worth of source material so you don't have the concern of writers getting tired around the middle of season 3, which is where most network shows tank creatively (Lost, Heroes, Grey's Anatomy, and on and on...). The only non-cable show that's an adaptation that I can think of is Legend of the Seeker and it's very good.
Yes there's way too much reality TV but I also agree with the above poster that it's better than watching the stuff from the 70s like variety shows, Hee Haw and Lawerence Welk. That was insufferable. But the good thing is that if I don't want to watch shows about people who are only famous for being famous like Paris and Kardashian and Speidi, then I just don't watch them because there's 200 channels and a device that records what I like without me having to remember the time and channel. Hallelujah!
The biggest telltale is that the stigma for doing TV doesn't really exist anymore. TV is now where aging film stars can thrive and get some great material. And you see film producers, directors and writers (Doug Liman, Jerry Bruckheimer, McG, Peter Berg) involved in TV projects while still having strong film careers.