We dumped our DirecTV after a 2 year contract last year. We use a Roku and have a Netflix and Hulu Plus account. I also had an Amazon Prime account so that automatically gives us the free streaming that was added last year. But the content is largely the same as Netflix so we only really use Amazon when we actually want to buy something. We also subscribe to Mog for music.
That's about $22 per month and we can watch or listen to as much as we like. That's about $100 less than I used to pay for a premium satellite package. When we want something random, I play music with the Pandora / Slacker / or Shoutcast channels. When I want news, I just put on Democracy Now.
But it isn't all perfect. You need to be willing to give up some of the benefits of cable / satellite and really learn how to make the most of the Roku. There will be shows that you might want to watch that (legally) will not be available for another year or so. There are a lot of streaming channels that you can't even use yet without a cable subscription (like HBO Go). Amid the myriad of crap that is on TV, there are a handful of shows that you might miss. Ultimately, they make it to Netflix or Hulu but you just have to wait it out.
That said, if you can dig through these streaming services, you will find things that you like. Many things that you might wonder why you hadn't seen them when they'd aired on TV. There is a lot of value in the current streaming offerings but there are still a lot of things that are missing. It will be a few years before streaming TV becomes the norm and people forget about cable completely.
If you can learn to live and watch TV in a different way that you have, then Roku (or similar) can be a great alternative to traditional cable or satellite. If you rely heavily on TV then you may be really disappointed. I've considered the cord-cutting experience to be somewhat life changing. We don't spend much time in front of the TV anymore. But we still generally find quality material to whatch when we do. It can take some adjustment and experiementation, but can be worthwhile and a substantial money-saver.