Or if you get a PC DVB card with the right codecs you can pickup 4:2:2 and MPEG4. (It is a little bit more difficult to setup and work with than a STB)
There are a bunch of channels on C-band, although mainly on DVB-S2, and you run into some on DBS sats. Not too many on regular Ku, but it's becoming more and more common. You're definately going to need mpeg4 pretty soon, as it is becoming more and more popular.
Subscription yes, but not always scrambled.
I've seen many dozen mpeg4 channels unencrypted, both HD and SD on a DBS sat. Most didn't last long, and went back to encrypted status, but there is still at least one nice mpeg4 HD channel that has been FTA for nearly 6 months now. You just have to keep looking, which I usually don't bother doing, but sometimes I stumble onto things. Unfortunately, sometimes these things require manual entry, ie won't scan in, and I haven't figured out a way of specifying mpeg4 manual channels via manual entry on the Coolsat or Diamond stbs I have.